INSTITUTUL DE GEOLOGIE-ȘI GEOFIZICĂ 7? /& 9l\ /> C--. ’zA Volum- special, editat eu ocazia celui CONGRES INTERNAȚIONAL .DE Paris, 1980 de*al 26-lea GEOLOGIE N 7 E V» CU R EȘTI 1980 Institutul Geologic al României igrV Les auteurs assument la responsabilite des donn6es- publiees Institutul Geologic al României INSTITUT DE GEOLOGIE ET DE G^OPHYSIQUE ANNUAIRE DE L’INSTITUT DE GEOLOGIE ET DE GEOPHYSIQUE TOME LVI Volume special, edite ă l’oeeasion du 26° C CONGRÎIS INTERNATIONAL DE GEOLOGIE Paris, 1980 BUCAREST 1980 A Institutul Geologic al României CUPRINS Pag. Săndulescu M. Analiza geotectonică a catenelor alpine situate în jurul Mării Negre occidentale...................................................... 5 Savu H . Geneza ofiolitelor ciclului alpin din România și vulcanitele calco- alcaline și alcaline asociate lor.............................................. 55 Cioflica Gr., Lupu M„ Nicolae I., Vlad Ș. Ofiolitele alpine din România : poziție tectonică, magmatism și mctalogeneză .... 79 Antonescu Em., Avram E. Corelarea dinoflagelatelor cu zonele de amoniți și de calpionele din Cretacicul inferior de la Svinîța-Banat ... 97 Ștefănescu M. Perioada depunerii flișului în Carpații Orientali............... 133 Istrate G. Natura și compoziția zeoliților din România........................ 143 Berbeleac I. Mineralizați ile de telur nativ și telururi de la Musariu, regiu- nea Brad (Munții Metaliferi), România......................................... 153 Ghenea C., Bandrabur T., Crăciun P ., Ghenea Ana. Contribuții la cunoașterea structurilor hidrogeotermale din România și a zonelor de perspectivă................................................. 169 Pop Gr. Zone, subzone și asociații caracteristice de calpionelide tithonic- neocomiene ................................................................... 195 Moisescu V., Popescu G. Biocronologia Chattian-Badenianului din România pe baza moluștelor................................................. 205 Institutul Geological României CONTENU Page Săndulescu M . Analyse geotectonique des chaînes alpines situees autour de la Mer Noire occidentale Savu H . Genesis of the Alpine Cycle Ophiolites from Romania and Their Associated Calc-Alkaline and Alkaline Volcanics Cioflica Gr., Lupu M., Nicolae I., Vlad Ș. Alpine Ophiolites of Romania : Tectonic Setting, Magmatism and Metallogenesis .... 79 Aut onescu Em., Avram E. Correlation des dinoflagellâsavecleszones d’ammonites et de calpionelles du Cr6tac6 infârieur de Svinița-Banat . . 97 Ștefănescu M. Time of Flysch Deposition in the Eastern Carpathians . . 133 Istrate G. The Nature and Composition of Romanian Zeolites...................... 143 Berbeleac I. Native Tellurium and Tellurides Mineralization from Musariu, Brad Region (Metaliferi Mountains), Romania..................................... 153 Ghenea C., Bandrabur T., Crăciun P., Ghenea Ana. Con- tributions to the Knowledge of the Hydrogeothermal Structures in Romania and of the Prospective Zones............................................... 169 Pop Gr . Zones, sous-zones et ensembles caracteristiques de Calpionellidaetitho- nique-nâocomiennes........................................................ 19$/ Moisescu V., Pop eseu G. Chattian-Badenian Biochronology in Romania by means of Molluscs....................................................... 205 XJGR Institutul Geologic al României Tehnoredactor: ILONA SANDU Traduceri: ADRIANA BĂJENARU, MARIANA BORCOȘ, ANCA BRATU, ADRIANA NĂSTASE, RUXANDRA NEGREA Ilustrația: VIRGILIU NIȚU Dat la cules: aprilie 1980. Buh de tipar: iunie 1980. Tiraj: 800 ex. Hirtie scris IA Format 70x100/56 g. Coli de tipar: 14. Com. 658. Pentru biblioteci indicele de clasificare 55(058) Tiparul executat la întreprinderea poligrafică „Informația", str. Brezo- ianu nr. 23 — 25, București — România Institutul Geological României ANALYSE GEOTECTONIQUE DES CHAÎNES ALPINES SITUEES AUTOUE DE LA MER NOIEE OCCIDENTALE1 PAR MIRCEA SĂNDULESCU2 Alpine teclonics. Tectogenesis (phases). Structural correlalion. Flysch. Geodynamics. Plate tectonice. Spreading. Subduction. Crusial shortening; Carpathians, Balkans, Dobrogea, Crimea. Abstract Geoteetonic Analysis of the Alpine C h a i n s Situated a r o u nd the Western Black Sea. The first part of the note is devoted to the description of the main tectonic units and of their structural correlation, in both Alpidic branch (Carpa- thians, Balkans, Pontides) and intracratonic north Ponto-Euxinic branch (North Dobrogea, South Crimea, Greater Caucasus). The position and the contents of the ophiolitic sutures are analysed. The problem of the age, sources and evolution of the flysch formation is especially examined. The main tectogenetic moments (phases) which have produced important defor- mation (generally accompanied by crustal shortenings) are described (Eokimmerian, Neokim- merian, Mesocretaceous, Pre-Gosau, Laramian, Pyreneean, intra-Lower Pliocene, intra-Badenian, intra-Sarmatian and Wallachian). A geodynainic evolution model is proposed. IXTKODUCTION L’analyse de l’evolution geotectonique des ehaînes alpine» voisines â la Mer Noire pose des probleme» multiple» et complexe». D’abord, puis- qu’il s’agit de ehaînes qui ont des structure» dont le detail de cdnnais- sanee est, encore, inegal. Ensuite puisque des conceptions differentes, voire meme antagoniste» jusque dans leurs principe» de base, gouvernent les syntheses plus ou moins etendues qu’on connaît sur les different» tron- gons de ces ehaînes. Enfin, puisque certaines connexions entre segment» 1 Note recue le 17 marș, 1980 et aceeptee pour publication Ic 21 marș, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. Institutul Geological României 6 M. SĂNDULESCU O sont sous la mer. Pourtant, bien que difficile et risquant d’arriver â des conclusions hypothetiques, telle analyse reste passionante et fort inte- ressante. II est fastidieux de vouloir faire un apergu historique exhaustif sur l’evolution des idees dans un areal de ces dimensions. Nous nous bor- nerons donc â rappeler quelques travaux gâneraux qui ont trăite sur les possibles corr&ations des chaînes alpines periponto-euxiniques 3. II s’agit d’A rgand (1924), de W i 1 s n er (1928) et de S ti 11 e (1953) qui, a des epoques differentes, ont considere l’ensemble Dobrogea septen- trionale-Crimde meridionale-Grand Caucase une chaîne alpine sâparee du rameau alpidique Carpatbes-Balkan-Pontides. Pour cette idee ont milite ce dernier temps Dumitrescu et Săndulescu (1968) et Săndulescu (1975). Par contre, Mo urato v (1960, 1964) suppose une liaison Crimâe-Balkan placant la Dobrogea septentrionale dans l’Europe hercynienne. Rappelons egalement que des reconstructions fondees sur les principes de la tectonique des plaques ont interesse cette region, ou bien dans son ensemble (D e w e y et al., .1973 ; B i j u-D u v a 1, Dercourt, Le P i c h o n, 1977), ou bien par segmenta (Rădu- lescu, Săndulescu, 1973; Bleahu et al., 1973; Hertz, S a v u, 1974 ; Bleahu, 1974 ; G r u b i c i, 1974 ; Dimitrievici, 1974; Boccaletti et al., 1974; Bergougnan, 1975; Four- quin, 1975; Hain, 1975, etc). Pour arrivei* au but proposâ — l’analyse de l’evolution geotectoni- que — nous examinerons d’abord la structure actuelle des deux grands ensembles alpins : le segment du rameau alpidique represente par les Carpathes, le Balkan et les Pontides et la chaîne Dobrogea septentrionale- Crimee meridionale. Ensuite nous examinerons rapidement la constitution des plate-formes voisines ă ces chaînes. Nous n’insisterons, bien sâr, que sur ies elements qui jouent un râie important dans la reconstruction evolutive. STRUCTURE ACTUELLE Carpathes Des Carpathes c’est, en premier lieu, la grande sigmoîde constituee par les Carpathes orientales et les Carpathes meridionales, qui interesse. D’abord, puisque la plupart de ces eiements passent dans le Balkan et ensuite parce que c’est elle qui vient en contact plus ou moins directe- ment avec l’Europe prealpine (les plate-formes) qui borde la Mer Noire. La «colonne vertebrale» de cette sigmoîde est representee par un ensemble d’unitâs charriees de l’interieur vers l’avant-pays, constituees 3 L’utilisation de la denomination Pontides seulement pour la chaîne situde sur le bord turc de la Mer Noire nous a empeche d’utiliser le mot peripontique pour l’ensemble des chaînes alpines riveraines de cette mer. Ainsi nous sommes arrives â une expression plus a barbare », mais qui ne prete pas aux confusions. Institutul Geological României 3 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 7 de formations cristallines (hercyniennes et plus anciennes) et sedimen- taires ndopaleozoîques et mesozoîques. Ce sont les nappes centrales est- carpathiques (Săndulescu, 1972) dans les Carpathes orientales, la nappe gdtique et les nappes supragetiques dans les Carpathes meridio- nales. La continuite le long de la chaine (Săndulescu, 1975), bien que complexe, des unites des deux trongons est soulignee aussi par le fait que des deux cdtes de la sigmoide on trouve des unites correlables : les Transylvanides ă l’interieur et les nappes du flysch dacique externe («Flysch Noir», Ceahlău, Severin) ă l’exterieur. Ce sont des unites ă ophiolites qui presentent les memes torsions que la sigmoide mentionnee. A l’interieur des Transylvanides se developpent les Dacides occidentales (Apusenides septentrionales et Carpathes occidentales centrales), ă l’exterieur des flyschs daciques externes se trouvent les nappes du flysch moldavien, dans les Carpathes orientales, et l’«autochtone» danubien, dans celles meridionales (planche I) Nappes centrales est-carpathiques, nappe getique et nappes supra- getiques. Ce sont des nappes de socle, generees par cisaillement (D u in i- tr eseu, Săndulescu, 1968 ; Săndulescu, 1967, 1972). A la constitution de chacune prennent part des formations cristallines (meso- et epimdtamorphiques, rarement des granites) et sedimentaires (meso- zoiques et par endroits du Paieozoique superieur). Les tectogeneses qui ont genere ces nappes sont cretacdes (tectogeneses dacidiennes — — Dumitrescu et al., 1962; Dumitrescu, Săndulescu, 1968), mate.rialisees dans trois phases (moments) principales : mesocre- tacee (fini-Albien), pre-Gosau et«laramienne» (fini-Senonien). La premiere est tres evidente dans les Carpathes orientales centrales. Lă un empile- ment de nappes (de haut en bas : nappe bucovinienne, nappe sub-buco- vinienne et connexe, nappes infrabucoviniennes) (Bercia et al., 1976 ; Săndulescu, 1972, 1975) dont les series sedimentaires ne depassent pas le Cretace inferieur, est cachete par une couverture post-nappe de- butant par le Vraconien ou le Cenomanien. Cette couverture recouvre aussi les restes d’un autre groupe de nappes, ă ophiolites(les nappes tran- sylvaines), qui surmontent la plus haute nappe ă schistes cristallins (celle bucovinienne), groupe qui appartient deja aux Transylvanides. Dans les Carpathes meridionales la tectogenese fini-Cretacd inferieur est egalement presente (surtout dans la pârtie est), des charriages supragetiques etant de cet âge. Mais lă la tectogenese fini-cretacee ă repris tout l’ensemble, remobilisant des anciens plâns de charriage ou recoupant d’autres. Le front des charriages fini-cretaces est represente, dans les Carpathes me- ridionales, par le front de la nappe getique ă la base de laquelle ă ete entraînde la nappe de Severin (ă ophiolites). Ce front correspond dans les Carpathes orientales ă la nappe de Ceahlău (toujours ă mafites). A ce moment-lă les nappes centrales est-carpathiques ont ete plus ou moins passives, etant affectees seulement par des retrochevauchements et re- troplissements (Săndulescu, 1967, 1975 b). Les series sedimentaires des nappes centrales est-carpathiques com- portent surtout des depâts mesozoîques (ante-Cretace superieur). Du Institutul Geological României igr/ 8 M. SĂNDULESCU 4 Permien ă volcaniques est connu dans quelques nappes infrabucovi- niennes, tandis que dans la nappe sub-bucovinienne il est tres mince et discontinu. Les sddiments paleozoiques superieurs manquent dans la nappe bucovinienne. Le Trias est franchement dolomitique dans les nappes buco- vinienne et sub-bucovinienne, tandis que dans les unites infrabucovinien- nes il est calcareo-dolomitique ă cacliet bitumineux. Le Jurassique' est mieux developpe dans la nappe bucovinienne, ou le Cretace inferieur est caracterise par une formation de wildflysch barr6mo(?)-albienne. Dans la nappe sub-bucovinienne le Jurassique et l’Eocretace sont minces et la- cunaires, comme dans celles infrabucoviniennes (â part la nappe la plus profonde oii l’on connaît une serie neojurassique-eocretacee detritique plus epaisse (sdrie de Dovgorun — H a i n et al., 1968 ; B î z o v a et al., 1971). Les nappes infrabucoviniennes correspondent â la nappe getique (Săndulescu, 1975, 1976). La nappe sub-bucovinienne se retrouve en ligne generales dans les nappes supragetiques. Les traits communs de ces unites sont (dans des limites tres generalisees) — pour la nappe getique et les nappes infrabucoviniennes : le Per- mien ă volcaniques, le Trias bitumineux, le Lias â facies Gresten; — pour la nappe sub-bucovinienne et les nappes supragetiques; le caractere tres accentul de ride avec des series sedimentaires particu- lierement minces et lacuhaires. La nappe bucovinienne ne trouverait pas ainsi de correspondants dans les Carpathes meridionales. Des rechercehs tres recentes (L u p u - donnees inedites)4 ont montre que, dans l’cxtremite meridionale des Monts Metallifâres, se d6veloppait unc zone caracterisee par la presence d’un wildflysch eocretace (notamment barr6mo-aptien) (couches de Căbești) oii des kippes sedimentaires de calcaires triasiques et de roches vertes ont ete mises en evidence. II serait un dquivalent du wildflysch bucovi- nien. Cette zone longe la marge nord du cristallin de Poiana Rusca (qui est supragetique), occupant ainsi une position plus interne que celui-ci, parfaitement comparable avec le domaine bucovinien. Plus au Nord de cette zone affleurent les unites ă ophiolites des Monts M6talliferes (encore plus internes) qui appartiennent aux Transylvanides, soulignant ainsi la position «bucovinienne » du wildflysch de Căbești. Entre les nappes supragetique et getique, dans les Carpathes meri- dionales d’une part, et la nappe sub-bucovinienne et les nappes infrabuco- viniennes, dans les Carpathes orientales, de l’autre part, donc dans la meme position tectonique, ou peut suivre un collier discontinu d’unites (nappes) pratiquement depourvues de schistes cristallins et fortement ecras^es et etirees. Ce sont: la nappe de Sasca-Gornjak (Săndulescu, 1975) en Serbie orientale et Banat, nappe de Reșița (Năstăseanu , 1978) au Nord du Banat, ecailles de Codlea et Poiana Mărului (Săndulescu, 1967), unite d’Argestru (Bercia, Bercia, 1970) nappe de Roziss (Hain et al., 1968). Ce collier d’unites ă formations sedimentaires (pour i--------------- 1 M. Lupu, recherches pour la carte geologique, feuille Deva (1980). \ Institutul Geologic al României occidentales; 7, banatites; 8, d^pressions molassiques n6ogenes- 10 M. SĂNDULESCU 6 la plupart triasiques, et par endroits aussi neopaleozoiques et/ou jurassi- ques) ecrasees entre deux groupes d’unites de socle marque une zone de fort raccourcissement de la croute et de «consommation» du socle sialique. Dans l’extremite sud des Carpathes meridionales, en Serbie orien- tale, les nappes supragetiques correspondent â la nappe de Morava, la nappe getique se prolonge dans les zones de Rjtan-Kucaj (?) et Timok (Grubi ci, 1974). La nappe de Șasea-Gornjak s’interpose entre les deux. A l’interieur de la nappe de Morava se trouve le massif serbo-mace- donien, Clement intermediaire entre Carpathes et Dinarides. Au Nord du Danube ce massif est recouvert par les molasses neogenes de la depression pannonienne. Sur son possible prolongement et les correlations Carpathes- Balkan nous reviendrons plus loin. Dans l’extremite ouest des Carpathes orientales l’ensemble des nap- pes centrales est-carpathiques plonge sous sa couverture post-tectonique (post-nappe) qui comprend des depots neocretaces, paleogenes et du Mio- cene inferieur. Encore plus ă l’Ouest les nappes et leur couverture sont recouvertes tectoniqueinent, par charriage, par la nappe de Dragovo- Petrova (equivalent est-carpathique du groupe Măgură des Carpathes occidentales), flanquee ă l’interieur par la zone des klippes pienines. Ce recouvrement tectonique s’est realise au cours du Miocene infdrieur. Transylvanides. Â l’interieur de la laniere d’unites de socle que nous venons de decrire on peut suivre une zone, â allure egalement sigmoîdale, qui groupe des unit^s ă ophiolites. Elle affleure dans les Monts Metalli- feres, y constituant les Metalliferes simiques, et se prolonge au-dessous de la depression de Transylvanie («zone ophiolitique» de Săndulescu et V i s a r i o n, 1978) vers l’Est et Nord-Est et sous la depression panno- nienne (Vi sar ion, Săndulescu, 1979) vers l’Ouest et le Sud- Ouest. Appartenant toujours aux Transylvanides et surmontant tectoni- quement La nappe bucovinienne des Carpathes orientales se developpent les nappes transylvaines. Le charriage de ces nappes, dont des klippes sd- dimentaires sont «emballees» dans le wildflysch eocretace de l’unite sous-jacente (nappe bucovinienne), est mesocretacA du meme âge que les nappes centrales est-carpathiques. Les «racines» des nappes transylvai- nes se trouvent du cotă de la «zone ophiolitique» situee dans le soubas- sement de la depression de Transylvanie. Elles sont sdpar^es de leur aire d’origine par le jeu conjoint des ecaillements et de lArosion post-nappes. Les nappes transylvaines sont connues seulement dans les Car- pathes orientales. II n’est pas pourtant impossible d’imaginer qu’elles aient recouvert, toujours tectoniqueinent, des unites de socle dans les Carpa- thes meridionales, etant ensuite entierement enlevees par l’drosion. Sui' la transversale des Monts Metalliferes on ne trouve plus actuelle- ment d’unites â vergence externe (comparables aux nappes transylvai- nes). Toutes les nappes ă ophiolites y sont dirigees vers le Nord ou le Nord- Ouest (Lupu, 1976; Săndulescu, 1975). Ce changement de vergences peut s’expliquer en rapție par l’âge diffdrent des deux grou- 4 ' t In sti tutui Geological României 7 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 11 pes de nappes : les nappes transylvaines mesocr^tacees, celles des Metalli- feres simiques pour la plupart n6ocr6tacees. Les formations sedimentaires qui accompagnent les ophiolites des Transylvanides appartiennent au Trias, Jurassique et Crâtac6 inferieur. Ce sont des depots surtout calcaires pour les nappes transylvaines et pour les nappes les plus meridionales des Metalliferes simiques et des flyschs ou wildflysch» pour les au tres nappes des Metalliferes simiques (P atr u- lius et al., 19661 Săndules cu, 1972, 1975; Lupu, 1974,1976). Les ophiolites des Transylvanides ont les caracteres d’une croute oceanique. Des recherches petrologiques et geochimiques autant dans les Monts Metalliferes (Savu et al., 1970; Savu, 1976), que dans les Carpathes orientale» (nappes transylvaines) (Russo-Săndulescu et al., sous presse) ont confirme cette hypothese (Rădulescu, Săn- dulescu, 1973; Hertz, Savu, 1974; Bleahu, 1974). Les connexions longitudinale» des Transylvanides sont difficiles ă suivrc. Vers le Nord et le Nord-Ouest elles sont relayees par les Pienides. Entre les deux s’interpose la faille nord-transylvaine (Săndulescu, V i s a r i o n, 1978) ă importante» translations horizontales et separant des compartiment» dont le deroulement des tectogeneses est different: seuiement cretacees au Sud, cretacees et tertiaires au Nord. Vers le Sud- Ouest les Transylvanides arrivent jusqu’au Nord de Belgrade (Visă- ri o n, Săndulescu, 1979). Suivant certam» auteurs (A n d j e 1- c o v i c i, Lupu, 1967; Bleahu, D im i a n, 1967) elles se raccor- dent avec les unites de Sumadja (et Vardar). Pour d’autres (Săndu- lescu, 1975), elles suivent un trajet contorsionne pour se retrouver dans les monts Mecsek. De lă, la connexion avec la zone ophiolitique des Dinarides, qui arrive jusqu’ă Zagreb, n’est pas trop difficile ă entre- voir. Mais, la solution de ce probleme depend beaucoup de la phylosophie — «stauberienne» ou «koberienne»—suivant laquelle on voit les rela- tions Dinarides-Alpes et la position avant les compressions du paleo- ocean tdthysien, sui' cette transversale. La question d^passe le cadre de cette note. Nappes daciques externes. Ă l’exterieur des nappes centrale» est- carpathiques et de la nappe getique se trouve un groupe d’unites ă mate- riei flysch et roches vertes. Ce sont la nappe du Flysch Noir (= nappe de Kameny potok=nappe de Civcin), la nappe de Ceahlău (â plusieurs digitations) et la nappe de Severin (Bleahu, 1962 ; B ă n c i 1 ă, 1958; Codarcea, 1940; Dumitrescu, Săndulescu, 1970; Grubici, 1974; Hain et al., 1968 ; Năstăseanu, 1975 ; S ă n- dulescu, 1975; Sikosek, Maximo viei, 1966; Ștefă- ne s c u, 1978 etc.). II s’agit de nappes depourvues de schistes cristallins, dont la masse principale est constituee de flyschs tithonique-cretace inferieur (par endroits — Ceahlău — aussi de depâts neocretace»). Dans la nappe de Severin des ophiolites typiques sont associees aux flyschs ; dans celle du Flysch Noir des roches mafiques, des cinerites et des radio- larites constituent un complexe d’origine intraplaque (Săndulescu C JA Institutul Geological României \ IGRZ 12 M. SĂNDULESCU 8 et al., 19755). Cette deuxieme zone â roches vertes, toujours d’allure sig- moidale, court parallelement aux Transylvanides, etant separee de celles-ci par un bourrelet d’unitâs de socle sialique. Affectees par la tectogenese mesocretacee, les nappes daciques ex- ternes ont subi le principal transport tectonique (par charriage, bien sur) ă la fin du Cretace. Dans les Carpathes orientales ces plâns de charriage ont subi des plissements, voire meme, par endroits, des reprises aussi, NW Se|sW ' NE Fig. 3. — Coupe geologique montrant la structure generale des Carpathes meridionales en Serbie Orientale (d'apres Grubici, 1974, simplifice). 1, autochtone danubien; 2, nappe infraseverine; 3, nappe de Severin; 4, nappe getique; 5, nappe de Morava (= supragetique); 6, molasses. dans les phases tertiaires (Săndulescu. 1975; Ștefănescu, 1976). Les nappes daciques externes depassent vers l’Est la vallee du Timok (consideree la limite Carpathes-Balkan), y etant representees păr les couches de Sinaia, appartenant ă la nappe de Severin. La posi- tion allochtone des couches de Sinaia du Nord-Onest de Belogradcic et de la valide du Timok est visible sur le păriclinal nord de l’anticlinal de Vrăka Ouka ou la serie sedimentaire jurassique-cretace superieur qui re- couvre lenoyau de l’anticlinal plonge sous le flysch tithonique-ndocomien (Couches de Sinaia) (Săndulescu, 1975, fig. 10, 16). Nappes des îlysehs moldaviens. Les Moldavides (D umitresc u et al., 1962; Dumitrescu, Săndulescu, 1968, 1970) grou- pent les nappes ă materiei flysch, externes par rapport aux nappes da- ciques externes. Ce sont des nappes entierement decollees de leurs substra- tums primaires et charriees vers l’avant-pays. On peut fort bien parler dans ce cas-lă d’une substitution de socle par sous-charriage. Les tectogeneses des nappes moldaviennes sont miocenes. La pre- miere s’est derroulee pendant le Miocene inferieur, etant fort probable- ment intra-burdigalienne. Les suivantes sont intra-badeniennc et intra- sarmatienne (phase moldave — Dumitrescu, Săndulescu, 1968). s Sandul eseu M., R u s s o-S ăndulescuD., Braț o sin I r i n a, M e- deșan A. (1979). Rapp. Arch. I.G.G., Bucarest. Institutul Geological României 9 CHAINES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 13 Les formations qui prennent part ă la constitution des nappes mol- daviennes sont d’âge Cretace inferieur et superieur, Paleogene et, par en- droits, Miocene (inferieur et moyen). Celles cr6tac£es et paldogenes sont, pour la plupart, de facies flysch. Le Miocene est g^nâralement molassi- que. Les arenites des flyschs ont une triple origine : provenant de l’avant- pays, provenant de l’arridre-pays (par rapport au sillon flysch le plus interne) etdes cordilleres emerg^es ă certains moments ă l’interieur de l’aire â sedimentation flyscheuse. Le materiei provenant de l’avant-pays est marque surtout par les debris de «schistes verts» du type connu en affleu- rement dans la Dobrogea centrale. La cordillere la plus evidente est celle dite cumane (Murgeanu, 1937) qui â fourni des granodiorites et schistes faiblement metamorphiques. Elle ne serait pas la seule. Pour ex- pliquer les arenites oligomictiques, riches en micas, de la nappe du Flysch Curbicortical (la plus interne nappe moldavienne des Carpathes orientales) on doit admettre une autre cordillere, situee probablement â l’interieur de l’aire de sedimentation de ce flysch qui pourrait la separer du sillon dacique externe. La nature sialique des debris provenant des cordilleres nous incite ă considerer que les socles primaires des flyschs moldaviens etaient plutot de type continental. Bien entendu, des segments de cette croute pouvaient etre amincis ou fortement fractures par des failles profondes. Ce serait une maniere de remobilisation qui la distinguât des plate-formes franche- ment cratonisees. Danubien. Dans les Carpathes meridionales manquent les nappes des flyschs moldaviens. Ainsi la nappe getique et la nappe de Severin recouvrent l’autochtone danubien, unite bordant la plate-forme moe- sienne â laquelle elle passe graduellement. Le socle danubien ă schistes meso- et epizonaux est riche en massifs granitiques. La molasse hercy- nienne est suivie par la transgression du Jurassique inferiem' auquel suivent des formations medio- et neojurassiques, du Cretace inferieur et superieur, couronnees d’un wildflysch turono-senonien (inferieur?). Le graben de la Cerna divise le Danubien en deux parties — Danu- bien externe et interne — caracterisees par des developpements lithologi- ques differents : surtout pelagiques ă l’interieur, surtout neritiques ă l’extericur. On ne retrouve pas l’autochtone danubien dans les Carpathes orien- tales. On peut supposer â la rigueur que les series sedimentaires (creta- cees) de celui-lâ passent lateralement â des facies flyschs actuellement representes dans les nappes moldaviennes. L’hypothese est difficile â prouver et l’histoire tectogenique plus âgee du Danubien parait s’op- poser ă une telle correlation. On peut imaginer aussi que l’aire de sedi- mentation des flyschs moldaviens se râtrâcissait progressivement, jusqu’â sa disparition complete. II ne faut pas oublier d’ailleurs que des la fin du Cretac6 le Danubien se trouve sous-charri6 au-dessous de la nappe getique et de la nappe de Severin. M Institutul Geological României igrZ 14 M. SĂNDULESCU 10 Subcarpathes. L’unite charriee la plus externe est representee par celle subcarpathique (pâricarpathique) (Băncii ă, 1958; Săndu- lescu, 1972; Săndulescu et al., 1977). Constituie surtout de depâts molassiques miocenes, qui conservent par endroits ă leur base des formations paleogenes, cette unite ă iti charriie pendant le Sarmatien. Le front de l’uniti subcarpathique — connu sous le nom de faille (ou ligne) pericarpathique — peut etre suivi (en affleurement ou par forages) tout le long des Carpathes orientales et aussi de celles meridio- nales, jusqu’au Nord duDanube. Lă il bute contre le prolongement septen- trional de la faille de Timok — ă translation dextre — qui semble «amor- tir» le mouvement de chevauchement. Balkan, Rhodope et Kraijstides II n’y a pas de limite tranchante entre Carpathes et Balkan, comme supposent certains auteurs (Bone ev, 1965, 1966; Gocev et al., 1^70). Une grande pârtie des unites et des zones lithofaciales des Carpa- thes meridionales se retrouvent dans le Balkan. Certainement, il y a des fractures importantes ă direction transversale, situees aux confins Carpa- thes-Balkan. Mais il s’agit surtout de failles tardi- ou ndotectoniques, qui recoupent des unites dâjă tectonisees ou des zones lithofaciales isopiques. Dans les schemes des auteurs citis ci-dessus les Carpathes meridionales sont restreintes aux affleurements des couches de Sinaia du Nord-Ouest de la Bulgarie, ce qui n’est pas conforme ă la realite. Les elâments particuliers qui apparaissent dans le «rameau alpi- dique» au Sud du Danube sont: le massif du Rhodope et les Kraijătides. Le Balkan se laisse divise en trois unites majeures longitudinalei (B o n c e v, 1965, 1966 ; 1974); le Prebalkan au Nord, la Stara Pianina et la Srednegorie au Sud. La zone de Kotel s’interpose entre le Prebalkan et la Stara Pianina et la zone de Strandja represente une pârtie de la Sred- negorie avec des particularitis specifiques. Du cote de la Mer Noire la depression de Varna joue le role d’avant-fosse, pas tonte ă fait typique.. Prebalkan. Si tu 6 au Sud de la plate-forme moesienne le Prebalkan represente en realite sa marge meridionale tectonisee. Une zone de transi- tion entre plate-forme et Prebalkan peut etre distinguee (B o n c e v, 1966, 1974). De ce point de vue, la liaison avec au moins une pârtie du Danubien est evidente. C’est surtout dans le Prebalkan interne qu’affleure la serie sedimen- taire complete. Elle va du Permien ă l’^ocene. La presence du Trias ă caracteres moesiens (gârmaniques) represente une particularite qu’on ne trouve pas dans l’autochtone danubien. Les facies du Jurassique et du Crdtace^ inferieur rappellent le Danubien externe ă predominance neri- tique. Â l’extremite sud du Prebalkan occidental (synclinal de Salaă) des facies pelagiques rappellent pourtant la zone de Svinița-Greben du Danubien interne (cf. Năstăseanu, informations orales). Un probleme particulier souleve l’existence des formations de flysch tithonique-neocomien situees sur le bord sud du Prebalkan interne et au \ IGRz Institutul Geologic al României 11 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 15 Nord du front de chevauchement de la Stara Pianina. Le developpement de ce flysch au milieu d’une zone dans laquelle prâdominent â ce niveau des facies calcaires peut suggerer l’hypothese d’une position tectonique. II ressemble beaucoup aux couches de Sinaia6 de la nappe de Severin, ce qui n’est qu’un argument suppl&nentaire pour son allochtonie, qui ă 4te d’ailleurs supposâe aussi par Joja (1967). L’hypothese de l’allochtonie de ce flysch entraîne aussi celle de sa position primaire. Avait-il avant une position externe ou interne par rap- port ă la Stara Pianina? Si on le compare avec la nappe de Severin, on doit le considârer plus interne, puisque la Stara Pianina s’enfonce dans son extremite nord-ouest sous cette nappe (voir plus haut et Săndu- lescu, 1975). En supposant qu’il s’enracinne devant le front de la Stara Pianina, on doit admettre qu’un sillon flysch, independant et relative- ment reduit en longueur, compliquait la bordure sud du Prebalkan. Stara Pianina. Elle represente l’« epine dorsale» des Balkanides (B o nc ev, 1966), avec une pârtie occidentale (Bercovica) et une autre centrale (ăipka), plus elevees, et une pârtie orientale abaissee (Luda Kamcija) (B o n c e v, 1966 ; H a j d u t o v et al., 1974). Au-dessus d’un socle cristallin (ă massifs granitiques) semblable ă celui du Prebalkan (Belogradcik) suit une serie sedimentaire du Paleozoique superieur (molas- sique â eruptions), Mesozoique (Trias, Jurassique, Cretacâ) et Paleogene (surtout fiocene). II est â remarquer que le facies danubien interne (Salas) est developpe sur la Stara Pianina aussi (Hajdutov et al., 1974). Des puissantes masses de flyschs du Cretacâ superieur et de l’Eocene s’y trouvent egalement, developpâes surtout dans la Stara-Pianina orientale (zone de Luda Kamcija). A la pârtie sommitale du flysch turonien et surtout dans le «flysch ă olistostromes» du Senonien et du Paleocene (flysch d’Emine) (qui est fort probablement un wildflysch), des klippes sedimentaires de calcaires et dolomies triasiques sont «emballâes» (N ac ev, 1977). Ce lithofacies rappelle beaucoup le Danubien ou, au meme niveau stratigraphique (Senonien), est developpe le wildflysch. La difference reside dans la nature des klippes sedimentaires, mais ga n’est qu’un probleme de source, qui ne change pas beaucoup le trăit g6n6ral .Des lambeaux de recouvrement surmontent ce «flysch» d’Emine, constituant la nappe de Karandyl (V î 1 c e a n o v, 1974, fide N a c e v, 1977) ă depâts carbonatâs triasi- ques et effusifs acides du meme âge. L’aire d’origine de tous ces elements allochtones (klippes sedimen- taires et lambeaux de recouvrement) est plus interne. Suivant N a c e v (1977), ce serait une zone appartenant toujours ă la Stara Pianina, mais plus interne que la zone de Luda Kamcija. Tenant compte du fait qu’un relais existe entre cette derniere et l’anticlinal de ăipka (B o n c e v, 1966) et qu’elle est situee devant le prolongement oriental de l’anticlinal, cette hypothese semble possible. On arrive ainsi ă distinguer dans la Stara 6 Nous avons pu constatei nous-memes cette similitude lors d’une excursion (1967) dans ; la râgion, guidâe par P. G o c e v. Institutul Geological României 16 M. SĂNDULESCU 12 Pianina deux zones plus ou moins paralleles : Berkovica- Sipka, plus in- terne, et Luda Kamcija, plus externe, ce qui explique la difference de facies du Cr6tac6 superieur (Hajdutov et al., 1974), au moins. Les tectogeneses principales de la Stara Pianina sont fini-Cretace («laramienne») et fini-Eocene moyen «pyreneenne» (Hajdutov et al., 1974). Une discordance anguiaire est citee (Hajdutov et- al. 1974) aussi ă la base du Maastrichtien dans la zone Sipka (donc dans la Stara Pianina interne), tandis que la sedimentation continue( ?) jusqu’au Paleocene (Nacev, 1977), dans la zone de Luda Kamcija. La tecto- genese «laramienne» suit aux flyschs neocretac^s, celle «pyreneenne» â ceux eocănes. Une molasse de l’Kocene superieur suit â cette dernidre tectogenese. La Stara Pianina, notamment la zone de Luda Kamcija, plonge vers l’Est sous la Mer Noire. Vers l’Ouest elle bute contre la faille du Timok. Par dessous les elements getiques de la Serbie orientale elle de- vrait se relier aux elements les plus internes du Danubien (voir les consi- derations faites ci-dessus). On peut donc conclure que le Danubien des Carpathes meridionales trouve son equivalent dans le Prebalkan et la Stara Pianina. Nous rappellerons les principaux traits communs : — la relative abondance en massifs granitoides paleozoîques et plus anciens; — les molasses hercyniennes riches en volcaniques aeides; — les facies lithologiques semblables, notamment ceux du Juras- sique inferieur, du Tithonique et du Crdtac^ inferieur, du Cretace superieur, speeialement du Senonien; — la position tectonique perimoesienne avec passage graduel ă cette plate-forme visible surtout dans le Prebalkan. II y a bien sur des differences aussi et la plus notable est le develop- pement du Trias dans le Prebalkan et la Stara Pianina, qui est absent dans le Danubien. C’est la consdquence d’une inondation differentielle, mais peut-etre aussi, en pârtie, d’une erosion plus active ante-Jurassi- que inferieur du cote danubien. Zone dc Kotel. Etroite et allongee, la zone de Kotel est situee entre la Stara Pianina orientale (Luda Kamcija) et le Prebalkan. Fortement tectonis^e, elle montre en affleurement seulement des formation» sedi- mentaires (triasiques, jurassiques, cretacees et eocenes). Des «olisto- stromes » y sont developpees (G a n e v, 1966 ; Hajdutov et al. 1974). Les faunes tdthysiennes trouvees dans les klippes sedimentaires constitu4es de depots triasiques compliquent beaucoup les choses, puis- que le Trias du Prebalkan et de la Stara Plaina montre des affinites moe- siennes (germaniques). Elles proviennent donc d’une aire bien plus meri- dionale, qu’on ne peut pas encore preciser. En s’engageant sur le chemin des hypotheses on peut se demander aussi si la zone de Kotel dans son ensemble n’a pas une position allochtone ? ! Srednegorie. Situde entre la Stara Pianina et le Rhodope, la Sred- negorie est caracterisee surtout par le large developpement du Cretacd (GR/1 Institutul Geological României 13 CHAtNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 17 superieur, avec des formations volcano-s^dimentaires andesitiques et chalco-alcalines au niveau du Senonien. Le socle cristallin surtout meso- metamorphique est surmonte par des formations permiennes (molassi- ques), triasiques, jurassiques et £ocretac6es, conservees dans des lambeaux discontinuă epargnes par l’erosion antds6nonienne. Nettement discordant sur le substratum et conserve actuellement dans des grabens longitudi- Fig. 4. — Correlations li- thostratigraphiques et tec- toniques dans la Srednc- gorie (d’apres Gocev et al., 1970). A, zone de Srednegorie: 1, marnes et marnocalcai- res ; 2, greș et calcaires greseux ; 3, and^sites, tufs A et tuffites ; 4, calcaires ar- gileux et silicites ; 5, con- glomerats ; 6, pictites, tra- chybasaltes, trachyand6- sites ; 7, greș. marnes.argi- lites, aleurolites; 8, cal- caires ; 9, soubassement du Cretace superieur. B, Srednegorie orientale et Ludaâ Kamcija : 1, for- mation charbons: 2, for- mation du flysch cenoma- nien-turonien; 3, forma- tion andisito-basaltique du B Cenomanien superieur; 4, formation and6sitique du Turonien: 5, formation and6sitique du Senonien inferieur-Campanien ; 6, for- mation carbonato-siliceuse (S6nonien inferieur-Cam- panien) ; 7, formation trachybasaltique (Maastrichtien); 8, formation de flysch (Maas- trichtien); 9, formation argilo-calcaire (Maastrichtien); 10, formation argilo-carbonatee- F — formation de flysch; KS — formation carbonato-siliceuse; A — formation andesilique: TB—formation trachybasaltique; G — Globotruncanes ; I—Inocerames ; H—Hippurites. naux (Bone ev, 1966 ; Gocev et al., 1970 ; Ha jdu tov et al., 1974), le Senonien comporte une sequence inferieure (qui monte jusqu’au Campanien — G o c e v et al., 1970) ă volcaniques andesitiques et de- pots marnocalcaires et une autre, superieure (maastrichtienne) groupant des flyschs et des volcaniques trachybasaltiques et trachyandâsitiques Institutul Geological României 18 M. SĂNDULESCU 14 (Gocev et al., 1970). Le long du rameau alpidique ce developpement voicano-sedimentaire du S^nonien est connu depuis Dacides occiden- tales (Vlădeasa) dans le Nord, mais surtout dans le domaine getique (Rusca Montană et Timok), la Srednegorie et les Pontides. La pârtie frontale de la Srednegorie est marquee, dans le Balkan central et occidental, par de grandes voutes anticlinoriales (Svoge, anti- clinal de Sredna Gora) (B o n c e v, D i m i t r o v, 1965 ; Ha j du t o v et al., .1974) ou les socles affleurent largement. Sur leurs bords externes elles chevauchent la Stara Pianina. Dans la Srednegorie centrale ce chevau- chement (charriage) est particulierement evident. Lâ le socle a des affi- nitds claires avec les metamorphiques getiques. L’anticlinal de Svoge (qui se prolonge dans la zone de Vidlic de Serbie orientale; And j el- c o v i c i et al., 1967) semble etre un element frontal, plus externe, sur- tout tenant compte des caracteres petrologiques des formations du socle, qui ont des affinites avec celles de Stara Pianina. Le Trias y est pourtant d’un autre facies, correlable avec le Getique frontal. Cet element frontal — Vidlifi-Svoge — serait depassâ, par charriage, dans la Srednegorie cen- trale ; il pourrait etre le lieu d’origine de la nappe de Karandyl et des klippes sedimentaires du «flvsch» d’Emine, voire meme du Trias de Kotel(?). La tectogenese principale de la Srednegorie est «laramienne», postmaastrichtienne. Le charriage frontal de la Srednegorie est du meme âge, mais il a 6t6 certainement repris lors de Ia tectogenese «pyreneenne », comme le montre la presence de l’Eocene sous le charriage de Triglav (Botev Vrîh) ( H a j d u t o v et al., 1974). La correlation de la Srednegorie avec la nappe getique ( S ă n- dulescu, 1975) accorde au contact frontal de la premiere une im- portance particuliere. C’est au-dessous de ce front que doivent s’« enra- ciner » les flyschs tithoniques et neocomiens de la nappe de Severin et de ses £ventuels equivalents (flysch de Trojan). En extrapolant les donnees connues dans les Carpathes meridionales, c’est entre le front de la Sred- negorie et le bord meridional de la Stara Pianina qu’on doit chercher les correspondants des nappes daciques externes. Et c’est le long de ce front que la cicatrice marquant le raccourcissement des socles daciques externes doit etre cherch6e. Les formations radiolaritiques et de type flysch de la zone de Kotel seraient originaires de cette cicatrice aussi, rappelant la nappe de Severin ! On arrive ainsi â suivre les traces du megasillon dacique externe (Săndulescu, 1973) depuis l’Ukraine subcarpa- thique (bassin de la Tissa superieure) jusque sur le bord de la Mer Noire (entre Burgas et Varna). C’est un Moment de correlation le long du «rameau alpidique » de grande importance. La zone de Strandja (= Istrandja), bien que gen&alement incluse dans la Srednegorie, presente des caractâres particuliers. II s’agit specia- lement du fait qu’il y a lâ des formations mesozoîques metamorphiques. II s’agit d’un Trias ă prddominance dolomitique et d’un Jurassique (infe- rieur-superieur) surtout phylliteux ă sequences calcaires ou dolomitiques; des roches vertes (coulees et tufs) sont assocides aux formations jurassi- Institutul Geological României 15 CHAtNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 19 ques. Les datations sont faites par des faunes (Schatalo v, 1958, 1967 ; Schatalov et al., 1972), bien que le metamorphisrne atteigne des degr^s eleves (schistes ă staurotide, dysthene). Les metamorphites mesozoîques surmontent un socle cristallin ă intrusions granitiques, pre- alpin. Tollmann (1965) suppose que les metamorphites mesozoîques et leur socle prealpin affleurent dans une fenetre tectonique d’au-des- sous la nappe de Srednegorie et de Stara Pianina; elle serait d’âge m6so- cretace, le Cenomanien non metamorphique transgressant les formations mesozoîques mdtamorphisees. Pour les auteurs bulgares (B o n c e v, 1965, 1966, 1967 ; G o c ev et al., 1974 etc.), la Strandja represente un vaste et complique anticlinorium, ou affleurent les elements cimmeriens de la Srednegorie; le metamorphisrne serait du ă deux phases tectog6- niques : cimmerienne ancienne (fini-Trias) au Sud et neocimmerienne (fini-Jurassique) au Nord. Â partla presence du metamorphisrne alpin, un trăit particulier sup- plementaire de la Strandja est le developpement du Jurassique ă voleani- tes basiques, qui n’est pas connu dans la Srednegorie. Les zones les plus proches oii l’on connaît des formations semblables ce sont le Danubien le plus interne (zone de Feneș — Năstăseanu, 1975, 1980) et les Pon- tides (Bergougnan, 1975a). Le rapprochement avec le Danubien interne soutient l’hypothese de Tollmann a la difference que la seule unite charriee par-dessus la Strandja serait celle de la Srednegorie, la Stara Pianina appartenant aussi au Danubien. La comparaison avec les Pontides plaiderait pour une position plus proche de Srednegorie et peut- etre plus interne. Kraijstides. Dans le sens large (B o n c e v, 1965, 1966, 1974 ; K a r a g i u 1 e v a, 1967) les Kraijătides seraient une zone tres allongee parallele au massif serbo-macedonien allant de la Mer Fg6e jusque dans, le Banat. Elles grouperont ainsi des elements tres differents (du Getique des Kraijătides proprement-dites, des masses cristallines rhodopiennes). Nous suivrons dans cette note la proposition de Grubici (1967) de restreindre les Kraijătides ă l’unite caracterisee par le developpement du ilysch tithonique, unite connue en Serbie orientale sous le nom de zone de Lu^nica. Dans les KraijStides (s.str.) ainsi definies affleurent, au-dessus d’un socle metamorphique ă massifs granitiques, une serie Trias-jurassique moyen carbonatee ă pass6es clastiques, couron£e d’un flysch tithonique. De l’interieur chevauche la nappe de Penkovtzy constituee de depots ordovicien-carboniferes (et par endroits permiens) non metamorphiques et triasique-jurassiques carbonates. Elle est d6coupee par l’erosion en plusieurs lambeaux parmi lesquels nous rangeons aussi 1« anticlinorium » de Trun. Cette nappe de Penkovtzy est le correspondent meridional de la nappe de Saska-Gornjak situee entre le getique et le supragetique (voir pârtie Carpathes). Â son tour, la nappe de Penkovtzy est chevauchee par le bord externe du massif serbo-macedonien qui est en grandes lignes la nappe de Morava (= Osogovo). Au Sud de Blagoevgrad ce chevau- 4 Ja In s ti tutui Geological României \ iGRy 20 M. SĂNDULESCU 16 chement met en contact le massif serbo-macedonien directement avec le cristallin du Rhodope; il a ete contoură jusque sur le bord de la Mer Fgde (M ere ier, 1966). Situees entre la Srednegorie er la nappe de Penkovtzy (= Saska- Gornjak) les Kraijstides (sensu stricto) ont une position «getique » tres interne. Elles arrivent vers le Nord jusqu’ă Niă(en Serbie orientale) ou elles sont depassees, par charriage, par les unites plus interne». Vers le Sud elles sont coincees entre les cristallins du Rhodope et du massif serbo- macedonien, butant aussi contre l’extremitâ nord-ouest du premier. Rhodope. Consideri un massif median classique. comme celui serbo- macedonien d’ailleurs, le Rhodope est constitue d’une grande masse cris- talline surmontee par des depots priaboniens, oligocenes et plio-quater- naires. Des volcaniques paldogenes s’y developpent aussi. Au Nord il vient en contact avec la Srednegorie et la Strandja, au Sud la zone de Vardar le contourne pour se raccorder â la cicatrice ophiolitique qui se- pare Pontides et Taurides en Asie Mineure. Si la marge nord est relativement tranchante (la faille de Maritza), celle meridionale pose beaucoup plus de problemes. Ainsi, en Thrace occi- dentale et dans l’îie de Samothrace ont ete trouvees des formations meta- morphiques mdsozoiques accompagnees d’ophiolites (cf. Walther, 1974) situees bien au Nord par rapport ă la cicatrice ophiolitique «tethy- sienne » (Vardar-Anatolie). Sont-elles en position allochtone sur le bord sud du Rhodope ou bien la cicatrice subit dans la Mer Egee nord-orientale des decrochements dextres importants? Pontides Les Pontides longent au Sud la Mer Noire. Elles representent dans l’Asie Mineure le «rameau alpidique» (Bergougnan, 1975, a, b, c; Fourquin, 1975; Bergougnan, Fourquin, 1976) s’âten- dant vers le Sud jusqu’ă la cicatrice ophiolitique qui longe au Nord les massifs de Menderes et de Kirșehir. Elles passent vers l’Est dans la chaîne du Petit Caucase, et vers l’Ouest au Balkan. Le front nord des Pontides se trouve sous la mer, ce qui rend tres difficile la realisation d’une image complete des unites qui prennent part ă leur constitution, mais 6galement une correlation complete entre Balkan et Petit Caucase. Les noyaux cristallins du socle pontique comprennent des formations metamorphiques et granites, hercyniennes et plus anciennes (Ugaz Dag, Daday, Anatolie du Nord-Ouest, Amasya etc.), recouvertes par une mo- lasse permo-carbonifere ă charbons7. Le Jurassique «flysch» (silto- argileux) riche en volcanites est typique pour les Pontides situees au Nord de la faille nord-anatolienne, tandis qu’au Sud de celle-ci (Anatolie du NO, Fourquin, 1975) les volcaniques manquent( ?). Tres carac- ’ Le Penno-Carbonifere marin de Pulur (Bergougnan, 1975a) peut ă la rigueur etre considere en position allochtone, comparable ă celui du NO de 1’Anatolie (Fourquin, 1975)? Institutul Geological României 17 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 21 teristiques pour les Pontides sont les flyschs senoniens et docenes (B o c- c a 1 e 11 i et al., 1968 ; Bergougnan, 1975a). Aux premiers sont associees des volcaniques andesitiques, ce qui rapproche clairement les Pontides developpees au Nord de la faille nord-anatolienne de la Sred- negorie du Balkan ! Le volcanisme trachyandesitique de l’Anatolie du Fig. 5. — Esquisse tectonique de l’Asie Mineurc (d’apres Bergougnan ct Fourquin, 1976, simplifice). 1, rameau alpidique; 2, suture ophiolitique; 3, rameau dinarique (formations metamorphi- qucs); 4, rameau dinarique (formations non metamorphiques); 5, faille nord-anatolienne; 6, faille?; 7, localit^s. NO est surtout patogene (Fourquin, 1975) se rapprochant ainsi de celui du Rhodope. Les ojihiolites dans les Pontides sont allochtones. La preuve est fournie par la nappe de Karayaprak (Bergougnan, 1975a) de la region d’Erzincan (Haut-Kelkit). Une position semblable doit etre consi- deree aussi pour les ophiolites qui surmontent les massifs cristallins de Ugaz Dag et Daday (Boccaletti et al., 1968) et en gdndral pour toutes les formations ophiolitiferes affleurantauNord de la cicatrice «tdthysienne ». L’hypothese de la position allochtone (â vergence nord) des ophiolithes du versant sud du Rhodope (voir pârtie Rhodope) trouve ainsi un cadre plus general. On arrive donc â la conclusion que le double deversement de la cicatrice ophiolitique «tethysienne» demontre dans l’Anatolie nord- orientale (B e r g ou g n a n, 1975) est general pour toute l’Asie Mineure et peut-etre meme pour la transversale de la Mer Eg6e septentrionale. 11 disparait pourtant, semble-t-il, le long de la zone de Vardar. L’ampleur du deversement septentrional des ophiolites ne serait pas negligeable, certains lambeaux etant assez eloignes de la cicatrice. Les affleurements les plus nordiques des Pontides le long du bord de la Mer Noire appartiennent toujours ă l’ensemble qui est similaire a Institutul Geological României 22 M. SĂNDULESCU 18 la Srednegorie. Que se passe-t-il avec les unites plus externes que celle-lă, notamment la Stara Pianina et le Prebalkan ? Elles doivent se trouver au Nord, sous la mer. Comme il est peu probable que la Srednegorie s’« autochtonise » brusquement sur la transversale d’Istamboul et tenant compte du fait que le plateau continental est relativement etroit au Nord de la Turquie, on peut supposer que leur sous-charriage au-dessous des Fig. 6. — Schema montrant la mise en place des unites charriees respectivement sur les autochtones pontique et taurique (d’apres Bergougnan, 1973). BP, bloc pontique; BT, bloc taurique; ZI, zones interm^diaires des p6ridotites d’Erzincan ; MI, restes des massifs intermediaires du type Kirșehir ; Șj, contact de base du melange ophiolitique post-Paleocene—ante-Lutetien superieur); ș2> contact de base de l’unite de l’Akdag d’Erzincan (post-Neogene); 1’3, failles posl- neog^nes. Pontides soit assez important. II faut remarquer dans ce contexte qu’â l’Est de la Mer Noire n’affleurent pas d’elements comparables â la Stara Pianina et au Prebalkan et que la chaîne du Petit Caucase chevauche le massif de Djirouly, qui est en position «moesienne» (Stil le, 1953). La cicatrice marquant les restes du m^gasillon dacique externe devrait se retrouver elle-aussi sous le front chevauchant des Pontides. Jusqu’oîi cette cicatrice se prolonge-1-elle sous la mer, ceci reste un probleme ouvert. Mais dans ce cas-lă aussi il est pour le moment difficile de lui trouver un correspondant dans le Petit Caucase. Dobrogea septentrionale Le tronșon de chaîne plissee qui affleure dans la pârtie septentrio- nale de la Dobrogea, au Nord de la faille de Peceneaga-Camena, repre- sente un segment de chaîne alpine qui ne se relie pas au «rameau alpi- dique ». Avec la Crimee meridionale et le Grand Caucase elle constitue une chaîne intracratonique, â l’opposition des Carpathes, Balkan et Pontides quisont deschaînes pericratoniques. (Dumitr eseu, Săndulescu, 1968, 1969, 1970). Deux unites principales affleurent dans la Dobrogea septentrionale : celle de Macin, interne (sud et sud-ouest), et celle de Tulcea, externe. Toutes les deux sont des unites de socle. Celui-ci est constitue de formations Institutul Geological României 19 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE. 23 cristallinnes hercyniennes(?) et plus anciennes, de granites hercyniens et de formations sedimentaires devoniennes et eocarboniferes. Le Trias et le Jurassique, affleurant surtout dans la zone de Tulcea, montrent des facies medit6raneens, des flyschs 6tant d6vdopp6s dans le Trias su- perieur et le Lias inferieur. L’unitâ de Macin est charriee (cf. O. M i- r ă u ț ă, donnees non publiees) sur celle de Tulcea, des lambeaux de re- couvrement y etant presents. Entre ces deux unites de socle est coincde une unite constituee de formations triasiques et de roches basiques (ophiolites selon Savu et al., 1980) : c’est l’unitâ de Niculițel. Son caractere d’unite allochtone depourvue de schistes cristallins lui confere un cachet particulier, mar- ■quant des raccourcissements assez importants de la croute (Eă du 1 eseu et al., 1976). Elle serait le temoin des obductions (Savu et al., 1970) eocimmeriennes, bien que les caracteres des roches basiques ne fussent pas clairement de type oceanique. Les tectogeneses alpines de la Dobrogea septentrionale se sont deroulees en deux moments : le premier â la fin du Lias (posterieur ă la deposition des flyschs) 8, un autre apres le Jurassique superieur et avant le Cretacd superieur (Săndulescu, 1978).- Pendant la premiere phase il est fort possible qu’eut lieu le charriage de l’unit6 de Macin et de celle de Niculițel, pendant la seconde le charriage («en bloc »?) de la Dobrogea septentrionale sur son avant-pays, notamment la depression predobrogeenne (superposee ă la plate-forme scythienne). Le prolongement vers le Nord-Ouest de la Dobrogea septentrionale, sous des molasses neogenes, a 6te precise par les forages jusqu’au Sud-Est d’Adjud (Barbu et al., 1970), ou elle finissait en coin entre la plate- forme scythienne et la plate-forme moesienne, qui viennent ainsi en contact le long d’une frac ture constituant le prolongement septentrio- nal de la faille de Peceneaga-Camena. Nulle part plus au Nord de structures alpines n’ont ete trouvees . Vers l’Est les structures de la Dobrogea septentrionale et leur cou- verture post-tectonique (Cretace superieur du synclinal de Babadag) plongent sous la mer. Leur raccord avec la Crimee alpine sera examine plus loin. Nous rappelerons pour le moment que les deux plate-formes ■qui limitent la Dobrogea septentrionale au Nord (scythienne) et au Sud (moesienne) passent aussi sous la mer. Crimee alpine Au Sud de la plate-forme scythienne, dans la Crimee meridionale, affleure un trongon de chaîne alpine connu sous le nom de «chaîne de Crimee”. Les plus anciennes formations qui y sont connues sont des flyschs du Triasique-Jurassique inferieur (flyschs tauriques), identiques aux flyschs du meme âge de la Dobrogea septentrionale. Au-dessus, avec une discordance fort bien exprimee (M u r a t o v, 1973), suit une serie terri- 8Patrulius et al. (1975) ont montrâ que les flyschs de la Dobrogea septentrionale n’6taient pas excluslveinent triasiques, mais qu’ils passaient dans le Lias aussi. 24 M. SĂNDULESCU 20 gene du Jurassique moyen, des facies calcaires et des flyschs du Jurassique superieur-Valanginien et ensuite, avec une nouvelle discordance, des calcaires eocretacâs (M urato v, 1973 ; Uspenskaya9). La cou- verture post-tectonique debute par l’Albien, comprenant aussi des de- pots du Cretace superieur et du Paleogene, meme du Miocene superieur (pârtie superieure de la serie de Maikop). A la pârtie sommitale des flyschs tauriques est developpe un tres interessant niveau â klippes sedimentaires (cf. Uspenskaya) renfermant des calcaires permiens, des roches triasiques et des basaltes â pillow-lava. Les deux tectogeneses les plus importantes sont apres le Jurassique inferieur (eocimmerienne) et dans le Cretace inferieur. La correspondence entre la «chaîne de Crimee» et la zone de Tulcea de la, Dobrogea septentrionale est tres claire. Le d6roulement des tectogeneses, la similitude des flyschs neotrîasique-liassiques, la position structurale identique (sur le bord sud de la plate-forme scythienne) sont des faits qui soulignent cette corr&ation. L’unite de Macin et celle de Niculițel n’affleurent pas dans la Crimee alpine. Elles peuvent pourtant se trouver sous la mer, au Sud de la câte meridionale de la Crimee. Une trace de leur existence, au moins de l’unite de Niculitel, sont les klippes sedimentaires de roches basiques qu’on connaît dans les niveaux d’« oli- stostromes». Cette connexion Dobrogea septentrionale-Crimee alpine se ferait par dessous la Mer Noire, dans les limites du plateau continental, largement developpe au Sud du golfe d’Odessa. Des failles transversales plus ou moins importantes peuvent decaler differents tronșons de cette zone de connexion, sans changer pourtant l’essentiel de la corr&ation. Plate-formes L’avant-pays du «rameau alpidique » examinâ ci-dessus (Carpathes, Balkan, Pontides) groupe des plate-formes de differents âges. La plus ancienne est la plate-forme est-europeenne, avec un socle prâcadomien et une couverture comprenant plusieurs cycles de sedimentation, depuis le Vendien jusqu’au Neogene. Au Sud de celle-ci est situee la plate-forme scythienne, ă consolidation hercynienne et ă couverture allant du Paleo- zoîque superieur jusqu’au Neogene egalement. La chaîne hercynienne situee au Sud de la plate-forme est-europâenne comprenait, ă part l’ac- tuelle plate-forme scythienne, les socles prealpins de la Dobrogea septen- trionale et de la Crimâe alpine. Cette pârtie sud de la chaîne hercynienne a ete remobilisâe au debut du cycle alpin dans la zone geosynclinale in- tracratonique qui correspondait â l’actuelle chaîne alpine Dobrogea du N— Crimee du S—Grand Caucase. Les diffârences qui existent entre la plate-forme scythienne et ces noyaux hercyniens remobilises seraient dues â une constitution differente de la chaîne hercynienne qui fut divisee en unites majeures longitudinales ă caracteres specifiques. 0 Lors d’une reunion internaționale ă Leningrad (1978) E. A. Uspenskaya a eu la tres grande aniabilite de nous faire connaître ses opjnions sur la geologje de la Crimee alpine. Institutul Geologic al României JGR./ 21 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 25 Au Sud de la chaîne alpine intracratonique et au Sud-Ouest de la plate-forme scythienne, au-delă du point de « disparition » de cette chaîne, se trouve la plate-forme moesienne. Son socle cristallin est antepaleo- zoîque. Pour les chaînes hercyniennes du Sud-Est europden elle consti- tuait un massif median (Du mitre seu et al., 1962). Sa couverture sedimentaire tres epaisse (par endroits plus de 6 km) comprend plusieurs cycles de sedimentation allant de l’Ordovicîen jusqu’au Tertiaire (Patrulius, 1960; Pop eseu et al., 1967 ; Paraschiv, 1975). Elle a subi des deformations qui etaient les echos des tectogeneses derou- lees dans les chaînes voisines. De grande» cassures crustales limitent ou dâcoupent la plate-forme moesienne. C’est d’abord la faille de Peceneaga- Camena, qui represente la limite septentrionale de la plate-forme et qui a facilite des transla tions dextres. Ensuite c’est la faille Călărași-Fierbinți, que nous denommons la faille intramoesienne, dont l’evolution est complexe, avec des translations dextres au debut et sânestres â la fin ( R ă d u - 1 e s c u et al., 1976). Ces cassures ont joue un role important dans l’evo- lution et la genese de la forme actuelle des Carpathes, en facilitant des sous- charriages differentiels de l’avant-pays. Vers l’Est la plate-forme moesienne passe sous la Mer Noire et devrait se prolonger sur le plateau continental. L’existence des zones a «rotite suboceanique (Malavitzky et al., 1970; Garkalenko, 1972) devrait interrompre la continuite de cette plate-forme (ă socle continental). Pourtant, des restes de cette plate-forme peuvent se trou- ver encore au Sud de la Crimee alpine, dans la pârtie est de la Mer Noire, se prolongeant dans le massif de Djirouly, du câte des Pontides. L’« ecla- tement» de la plate-forme moesienne serait un effet de l’« ouverture» de la Mer Noire, mais le debut de celui-ci est encore difficile a preciser. II semble pourtant qu’il soit posterieur aux ouvertures tethysiennes da- tant du Trias. Nous reviendrons sur ce probleme plus loin. Correlation generale des grands ensembles strueturaux En guise de conclusions ă l’analyse de la structure actuelle nous essayerons de delimiter les grands ensembles strueturaux, afin d’avoir un point de depart pour les reconstructions evolutive». La plus compli- quee est la correlation le long du « rameau alpidiquc», sur laquelle nous nous arreterons en particulier. C’est K o b e r (1931, 1933) qui & developpe la « philosophie » de la division des chaînes alpines de l’Europe en deux rameaux : alpidique, du cote de la plate-forme europâenne, et dinarique, du cote de celle afri- caine. Ils seraient separes par des massifs medians (= Zwichengebirge) ou par des cicatrice» (= narben), le long desquelles ceux-ci disparaissent ou manquent. Plus tard, le developpement de la connaissance sur la struc- ture des chaînes plissees a montre que la plupart des massifs medians (Anatolien, Transylvain, Pannonien) faisaient pârtie d’un rameau ou d’un autre, s’integrant dans la structure generale de ceux-ci. Avec l’«ar- rivee » de la tectonique des plaques, une nouvelle symetrie s’imposait, Institutul Geological României igr/ 26 M. SĂNDULESCU 22 dont l’axe devraient etre les restes de l’ancien ocean tethysien (meso- geen). On est parti donc ă la recherche des marges continentale», europe- enne et africaine, en meme temps que des restes de l’ancien oc6an. Pour ce qui concerne l’aire ă laquelle se rapporte notre analyse,. il semble qu’une solution assez ferme ait eteacquise pour les chaines situees au Sud de Belgrade. En effet, la limite interne de la zone de Vardar et de la cicatrice qui lui correspond dans l’Asie Mineure marque en meme temps la limite meridionale du continent europeen (D e r c o u r t, 1970 ; Au bou in et al., 1970; Au bou in, 1973; Bergougnan, F o u q u i n, 1976 ; B i j u-D u v a 1 et al., 1977 etc.), et en meme terapii du «rameau alpidique». De Belgrade vers le Nord, les choses se compli- quent et les Solutions different suivant les modeles choisis. Dans ce contexte l’analyse de la position des Transylvanides est de premiere importance. II n’est pas dans notre intention d’entrer dans les details de la struc- ture et de la paleogâographie des Alpes. II faut tout de meme precisei* que le dilemme consiste â choisir entre des modeles plațant le paleo-ocean tethyisen au Sud des ensembles Austroalpins ou au Nord de ceux-ci. Ce dilemme s’etend aux Carpathes egalement. L’ensemble Austroalpin correspond dans les Carpathes aux Dacides occidentales. Celles-ci sont separees des unitds plus europeennes â socle sialique par les Transylvani- des ă croute ocdanique. Comme les Transylvanides peuvent etre corre- lees avec la zone piOnontaise (S ă n d u 1 e s c u, 1975, 1980), on constate que le probleme est le meme sur la transversale des Alpes orientales que sur la transversale des Carpathes. En correlant les Transylvanides avec la zone de Vardar (voir cha- pitre Carpathes) «africanise »-t-on tout l’ensemble des Dacides occiden- tales et de 1'Austroalpin ? Ce n’est pas si fac ile, puisque les particu Iar iteR des tectogeneses et l’evolution sedimentaire de celles-ci aussi bien dans l’Hercynien qu’au cours de l’Alpin sont plus proches de l’evolution euro- pdenne. On suit difficilement l’hypothese de C h o r o w i c z et G e y s- s a n t (1976) qui relie l’ocean piemontais ă celui dinarique par l’internui- diaire d’une paleofaille transformante Split-Vienne, qui interrompt la. continuite, pourtant evidente, de l’Austroalpin et des Dacides occidentales. On ne peut pas egalement placer le Gâtique sur la marge nord-appulienne et relier Codru et Bihor avec le Rhodope (B i j u-D u v a 1 et ah, 1977), pour la bonne raison que le Getique est plus externe (plus « europeen »} aussi bien par rapport au Rhodope qu’aux Monts Apuseni (Săndu- lescu, 1975). II faudra donc chercher un modele qui ne pjacera pas l’ensemble Austroalpin-Dacides occidentales dans une position « africaine», mais qui permettra aux ophiolites transylvano-piemontaises de repre- senter les restes d’une pârtie du paleo-ocean tethysien, situe au Sud de la marge continentale 6urop6enne (T r u m p y, 1975). On pourrait se demander ainsi si la cassure tethysienne n’avait pas bifurquee isolant entre deux zones oceaniques un domaine continental qui grouperait les unites de l’ensemble Austroalpin-Dacides occidentales. En partant des Transylvanides et du Vardar vers la plate-forme moesienne on constate que deux groupes d’unitds peuvent etre correlees Institutul Geological României 23 CHAINES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 27 ă longue distance: les unites daciques externes, d’une part, et les unites ă socle sialique, representes par les nappes centrales est-carpathique, getique, supragetique, Srednegorie et Pontides, d’autre part. Le massif serbo-macedonien et le Rhodope longeaient ce dernier groupe du cote de la zone de Vardar. Le megasillon dacique externe correspondait â une zone ă croute aminele fortement fracturee, avec genese d'ophiolites intraplaques (exem- ple : nappe du Flysch Noir), qui par endroits passait ă une croute franche- ment oceanique (exemple : nappe de Severin). Ce megasillon longeait la marge plus ou moins mobilisee de l’avant-pays qui subissait des subsi- dences plus (facies flyschs) ou moins (facies carbonates) accusees. Par endroits ce megasillon pourrait se retrecir fortement, ă sa place ne restant qu’une cassure crustale profonde. De l’autre câte du megasillon le domaine continental groupant les unites de socle mentionnees ci-dessus etait assez vaste, avec une confi- guration plutot compliquee. II a subi des raccourcissements evidents sur- tout dans sa pârtie mediane marquee par les unites constitutes seulement de formations sedimentaires (nappes de Roziss, d’Argestru, de Reșița, de Șasea-Gornjak et de Penkovtzy). Le «rameau alpidique» est separt de la chaîne intracratonique Dobrogea septentrionale-Crimee meridionale par la plate-forme moesienne. Â aucun moment de son histoire alpine elle n’a ete reliee â d’elements appartenant au «rameau alpidique », notamment aux Carpa- thes. Cette liaison (Hertz, Savu, 1974; Savu et al. 1980) n’est pas possible, puisque les unites de la Dobrogea septentrionale s’arretent avant de toucher les Carpathes (cf. donnees de forages) et aussi puisque ces deux zones mobiles etaient separees par une zone cratoniste represen- tant le prolongement nord-ouest de la plate-forme moesienne. LE PROBLEME DES FLYSCHS Tout le long du «rameau alpidique » et aussi dans la chaîne intra- cratonique Dobrogea septentrionale-Crhnâe meridionale, les formations de flysch sont developpees â differents niveaux stratigraphiques, avec des positions tectoniques diverses. Comme nous l’avons deja mentionne (Săndulescu, 1975), suivant les caracteres des rythmes, le rapport arânites-lutites et le contenu en car- bonate ou en silice, on peut distinguer plusieurs lithofacies majeurs de la formation du flysch : — flyschs type «couches ă hieroglyphes » constitues d’arenites et lutites (gâneralement argileuses) en proportions egales, groupees en ryth- mes binaires minces d’epaisseur relativement egale; — flyschs greseux, dans lesquels les arenites sont largement develop- pees, occupant la plus grande pârtie des rythmes; — flyschs schisteux, dans lesquels les lutites sont predominantes, mais pour lesquels la rythmicitd des niveaux arânitiques doit toujours exister; \ IG R/ Institutul Geological României 28 M. săndulescu 21 — flyschs calcaires, generalement ă trois composants (ardnite,s lutites et calcaires fins ou marnocalcaires), dont deux alternant rythini- quement et le troisi^me (calcaires ou marnocalcaires) s’intercalant d’une maniere pararythmique; — flyschs siliceux, dont les arenites ont des ciments siliceux et les lutites sont argileuses et souvent silicifiees. Des types intermediaires sont souvent developpes, marquant Ies passages lat^rau x ou sur le verticale d’un type fondaniental h l’autre. Les flyschs n'ont pas, en gtn&ral, une position prâfârentielle. Ils se developpent aussi bien dans des zones ăcroute oceanique, amincie ou con- tinentale. Les exemples se trouvent dans plusieurs secteurs des chaines e.xaminees, sans liaison avec l’âge des flyschs. Les flyschs triasiques tauri- ques (et equivalents) sont developpes dans une unite ă socle sialique, tandis que dans la zone ăophiolites il n’y a que sedimentation carbonatee. Les flyschs tithonique-neocomiens montrent une plus grande diversifi- cation : ils se trouvent aussi bien dans les zones pourvues de croute ocea- nique ou amincie (flysch de Severin, de Ceahlău, Flysch Noir, flyschs des Transylvanides), que dans des unites â socle sialique (flysch des Kraij- Stides, flysch de Pojorîta et equivalents dans la nappe bucovinienne). On constate quand meme que la majeure pârtie des flyschs tithonique- neocomiens sont lies ă des zones oii se developpent les ophiolites (fait remarque recemment par D u r a n d D e 1 g a, sous presse), 6tant generalement du type flysch calcaire. Les exceptions citees ci-dessus mon- trent pourtant qu’il n’y a pas lâ une regie, que certains schemas de la tec- tonique des plaques essayent d’imposer. Les flyschs barremo-albiens, lă-ou ils sont connus, montrent une dis- position semblable â ceux tithonique-neocomiens. Dans ce sens, le modele des Carpthes orientales est tres instructif. Le flysch debute dans le mega- sillon dacique externe au Tithonique (superieur ?-Ș tefănesc u, 1978) et monte jusqu’ă l’Albien. AprOs les flyschs calcaires suivent au Barremien- Aptien des flyschs ă lithofacies differencies — greseux vers l’interieur. de plus en plus proches du type «couches ă hieroglyphes » vers l’exterieur, et de plus en plus atypiques vers l’avant-pays (dans ce cas precis il s’agit de la pârtie inferieure et de la pârtie moyenne de la serie des Schistes Noirs des Moldavides10). A l’Albien la sedimentation flysch s’est deplapee (migree) vers l’exterieur (Moldavides), dans les Dacides externes se de- veloppant, ă cote des flyschs et vers l’intereur, des formations molassi- ques (Conglomerats de Bucegi, Ciucaș, Ceahlău). Ce cycle: flyschs cal- caires-flyschs diffdrenci6s-r6trecissement des facies flysch (Săndu- lescu, 1975) se repete encore une fois dans les Moldavides du Seno- nien au Miocene inferieur. Les flyschs du Cretace superieur, du Paleogene et, par endroits, du Miocene inferieur sont surtout lies aux unites pro- venant des zones ă socles sialiques (Moldavides, Srednegorie, Pontides, 10 II est important de souligner que dans les Moldavides (â l’exception du Flysch Curbicortical) les vrais facies flysch n'apparaissent qu’â l’Albien, et meme â ce niveau ils ne sont pas g6n6ralis6s. Institutul Geologic al României 25 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 29 Prdbalkan). II y a pourtant des flyschs, surtout paleogenes, qui surmon- tent des unites provenant de zones ă croute oceanique ou amincie, mais qui ^taient ou bien cicatris^es (nappe de Ceahlău recouverte pai' le flysch de Șotrile), ou bien affectees deja par une premiere tectogenese (unites pienines avec les flyschs paleogenes, flysch de Botiza, flysch du groupe Măgură interne). Cette particularite des flyschs neocretaces et paleogenes semble etre determinee par le fait que nulle part, dans l’aire analysee au moins, des spreadings plus jeunes que le Cretace. inferieur ne sont connus et que les zones ă croute oceanique ou amincie ont ete cicatrisees (fermees) eu totalite ou en pârtie des la fin du Cretace inferieur. Les flyschs pric^dent ou succedent aux tectogeneses11. Gdneralement, les flyschs sont entraîn^s dans des nappes de charriage ou sont fortement pliss6s. C’est donc la position pretectogenique qui est la plus frequente. Meme dans ce cas, il y a deux variantes: les flyschs precedent toute tec- togenese importante (determinant des racourcissements plus ou moins accusăs de la croute) ayant affectee l’aire de leur depot, ou les flyschs suc- cedent ă une tectogeneseetprecedentunedenxieme qui les entraîne dans des deformations de type alpin. On pourrait donc distinguer des flyschs nettement pretectogeniques (pretectogeniques stricto sensu) et des flyschs intertectogeniques. Cette distinction n’est pas li6e a l’âge des flyschs : des flyschs paleogenes peuvent etre pretectogeniques stricto sensu dans certaines zones (Moldavides) et intertectogeniques dans d’autres zones (Pienides). II y a pourtant aussi des flyschs post-tectogeniques. Les plus con- nus sont le flysch de Podhale de la couverture post-tectogenique des Car- pathes occidentales centrale» et les flyschs oligo-miocenes de la couverture post-tectogenique des Dacides orientales. Le flysch de Șotrile est egalement Fig. 7. — Coupes schematiques montrant le mechanismc des charriages successifs des nappes â materiei flysch (d’apres M. Săndulescu, 1975, simplifice). 1, formations pelagiqucs ; 2, formations flyschs: 3, formations conglomera liques. 11 La tectogenese est une pârtie seulement de Forogenise. Cette dernicre comprend deux processus qui transfonnent une zone geosyndinale en «chaîne plissee • : les teetogc- neses et les morphogeneses (S t i 1 l e, K o b c r, I< r a u s. IT i 11 s, M el z ete.). Dans ce contexte rechercher si les flyschs sont« synorogCniques » (.1 i p a, 1978) ne rime ă rien, le temps de l’orogenese couvrant toute la păriode qui correspond â un cycle orogenique. Institutul Geological României 30 M. sanduuescu 26 un flysch post-tectogenique, se developpant dans la couverture post- nappe de la nappe de Ceahlău. Bien que cette relation des flyschs avec la tectogenese soit rare, elle existe quand meme, et doit etre retenue.12 Les flyschs ont des sources de differents types. C’est surtout dans les Carpathes que le probleme des sources des aiAnites des flyschs a ete etudie (Ksiazkiewicz, 1959, 1960—1963; Murgeanu et al., 1963; S 1 a. s k a, 1969 ; Contescu, M i h ă i 1 e s c u, 1970 ; Contescu, 1969 etc.). On s’est aperșu des le debut du siecle que les flyschs carpathi- ques recevaient des debris provenant egalement de l’avant-pays («exoti- ques») et des zones carpathiques plus internes. C’est aussi depuis long- temps (Murgeanu, 1937) que des etudes lithologiques ont montre la necessite d’admettre l’existence des cordilleres ă l’interieur des aires ă sedimentation flysch. Ce n’est pas sur la position que les differentes sour- ces d’arenites puissent avoir par rapport ă la zone de sedimentation des flyschs que nous voulons insister, mais sur la variation dans le temps de la puissance de ces sources et sur le fait qu’elles n’alimentaient pas des aires de dimensions constantes. Nos considerations concernent surtout les flyschs carpathiques. La source externe situee dans l’avant-pays est marquee surtout par les debris de Schistes Verts (de type Dobrogea centrale). Ils se trouvent dans les depots du Cretace, du Patogene et du Miocene inferieur des Moldavides. Sa puissance a connu des moments paroxysmaux (con- glomerats) au Paleocene, Oligocene et Miocene inferieur, mais l’aire de dispersion des debris qu’elle fournissait s’est restreinte progressivement (D u m i t r e s c u et al., 1970) 13. Repandus pendant le Cretace inferieur sur la majeure pârtie du domaine paleogeographique des Moldavides (ils font defaut seuiement dans les depots albiens du Flysch Curbicortical), les debris de Schistes Verts n’arrivent au Senonien que jusque dans la pârtie mediane-interne de l’aire de sedimentation de la nappe de Tarcău, ă l’Rocâne seuiement jusque dans la pârtie mediane de cette meme nappe, dans l'Oligocene seuiement jusqu’au front de cette nappe et au Miocene inferieur pas plus que dans les plis marginaux. On constate qu’ă la limite Rocretacd/N6ocr6tace la limite de la dispersion maximale des debris fournis par l’avant-pays fait un saut important, determine peut-etre par l’echo des tectogeneses mesocretacees qui s’etaient achevees plus â l’interieur. Au contraire, depuis le Senonien jusqu’au Miocene inferieur, cette limite subit un deplacement graduel lie seuiement ă la migration de l’axe du sillon flysch. Sur le fond de l’ac tivite quasi-permanente de la source situee dans l’avant-pays est venue s’ajouter, pendant le Vraconien et le Cenomanien (peut-etre meme une pârtie du Turonien), une autre source. II s’agit de la cordillere cumane (M u r g e a n u, 1937), dont l’activite est marquee 12 Situation remarquee aussi par D e b e 1 m a s (1970). 13 D u m i t r e s c u I., .Joja T li., Săndulescu M., Alexandresc u G r., Săndulescu J., B r a t u E., Ștefănescu M., M 1 c u M. Rapp. Arch. I.G.G., București. Institutul Geological României 27 CHAINES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 31 par les debris de granodiorites, qui a surgi au milieu du domaine des Mol- davides. Les debris provenant des deux sources se sont m&angds seule- ment ă l’exterieur de la cordillere, qui faisait barriâre. Cette cordillere est un exemple de source ă activite limitee, et, parait-il, delargeur reduite (guirlande d’îles, allongees le long du sillon?!). Une source qui ddbitait un materiei tres «monotone » a fourni les ardnites du Flysch Curbicortical : surtout du quartz, accompagne de la muscovite. Elle etait placee ă l’interieur de la zone de sedimentation du Flysch Curbicortical, la separant peut-etre du megasillon dacique externe. La maturite avancee des arenites de ce flysch suppose ou bien une consti- tution particuliere de la source, ou bien une longue alteration du materiei detritique, ce qui suggere une assez grande largeur. Cette cordillere — que nous denommons pdrimoldavienne, vu qu’elle longeait ă l’interieur le domaine moldavien — est comparable avec la cordillere silesienne des Carpathes occidentales (K s i a z k i e w i c z, 1959; 1960 — 1963), en pârtie par sa position et par ses dimensions. 11 faut preciser pourtant que la nature des debris fournis par les deux cordilleres n’est pas tout ă fait comparable, prouvant des constitutions differentes. Des relais pourraient exister entre les deux. Les sources qui ont engendre les arenites des flyschs daciques ex- ternes avaient une constitution variable et des positions diverses. Une. source etait vraisemblablement le domaine central est-carpathique, qui n’âtait pas encore tectonise (les nappes y sont mesocretacees), mais qui subissait des erosions evidenciees par le caractere discontinu des formations sedimentaires mesozoîques des nappes qui s’y etaient formees. Mais il ne s’agissait pas seulement de cette source. Les differences qui existent entre les arenites de la nappe du Flysch Noir et de la nappe de Ceahlău mon- trent que d’autres soru'ces encore etaient actives. L’abondance de debris de roches basiques dans les flyschs barremo-aptiens de la nappe de Ceahlău (Săndulescu, 1964) impose la conclusion que des morceaux de socle de ce type du megasillon meme sont arrives dans la zone d’erosion. Ce serait le resultat des compressions fini-Neocomien qui eussent ete prouvees dans certains secteurs de la nappe de Ceahlău (Ștefănescu. 1973), peut-etre contemporaines des ecaillages d’âge austroalpin du domaine central est-carpathique ( S ă n d u 1 e s c u, 1975, 1976). La constitution supposee tres complexe du megasillon dacique. externe (Să ndu 1 es c u, 1973) souligne la possibilite de l’existence de ces sources multiples. L’examen du probleme des sources sur la seule transversale des Carpathes orientales, que nous venons de faire, montre combien est-elle complexe, la paleogeographie des bassins sedimentaires du flysch. Certai- nement, sur d’autres transversales d’autres problemes sont ă resoudre. Nous nous bornerons seulement ă constatei' que : — les sources des arenites constituant les flyschs ont des positions variees; — la duree de leur activite est tres variable, depuis quelques millions d’annees jusqu’ă plusieurs dizaines de millions d’annees, approehant dans un seul cas (l’avant-pays) la centaine; Institutul Geological României \ «GR 32 M. SĂNDUUESCU 28 — la configuration des bassins ă sedmentation flysch etait complexe et changeante; — la seule analyse des directions de transport, sans l’analyse petro- graphique des arenites, ne suffit pas pour solutionner ce probeme paieo- geographique. La sedimentation flysch s'installe quand des conditions spMfiques de subsidence et de transport rythmique sont acquises. On enfonce des portes ouvertes en soulignant que non pas toutes les series marines clastiques et epaisses sont des flyschs. La condition de rythmicite, et pour certains auteurs celle du transport par courants de turbidite, est primordialement necessaire. La coexistence temporelle des flyschs, aussi bien avec des for- mations pelagiques ou neritiques calcaires, ou avec des molasses, montre que ceux-ci n’ont pas une position unique et fixe dans l’histoire d’une « chaîne plissee ». Les rapports qui s’etablissent entre sedimentation flysch et tectogenese (voir ci-dessus) renforcent cette conelusion. Essayer d’expliquer par quoi les conditions specifiques de la sedi- mentation flysch sont determinees, c’est plus dirficile. Les conditions de mobilit6 speciale aussi bien de la zone de sedimentation que des sources doivent jouer un role important. Suffisent-elles ? JSOCHHONTSME ET BEtEROCHIIONISME DES TECTOGENESES La succession temporelle et la distribution arfele des tectogeneses montrent que les processus de d^formation qui ont pris part â l’ătablis- sement de l’architecture d’une «chaîne plissee» ont des intensites et des formes variables. C’est pourquoi la correlation des unites ayant subi des deformations au meme moment et de la meme qualite est importante. Nous allons analyser surtout les tectogeneses importantes qui ont determine des raccourcissements de Ia croute ou, au moins, des plissements intenses: c’est ce qu’on appelle d’habitude tectogeneses paroxysmales. Mais ce qui est important dans une zone, peut etre secon- daire dans une autre, ou meme manquer dans une troisieme. Tectogeneses eoeiinmeriennes. La Crimee meridionale et la Dobro- gea septentrionale etant le ..locus tipicus” de la tectogenese eocimerienne, il est utile de remarquer que les dernieres donnees stratigraphiques prfeisent le moment de son developpement vers la fin du Lias (voir parties Crimee et Dobrogea). Sa correlation le long de la chaîne Dobrogea du Nord-Crimee du Sud est tres claire et precise. Elle y est de type paro- xysmal. Lc rajeunissement de la tectogenese eocimmerienne, determine par les precisions stratigraphiques acquises dans la region ou elle a ete definie, rend difficile sa correlation avec d’autres endroits ou elle a ete censee d’etre reconnue, mais dans son sens «classique», c’est-â-dire placee ă la fin du Trias. II s’agit surtout de la Strandja (voir pârtie Balkan), ou un metamorphisme de cette âge est suppose. Au contraire, dans les Pontides meridionales (Anatolie du Nord-Ouest), la mise en Institutul Geological României 29 CHAÎNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 33 place de la nappe des formations permiennes, apres le Lias inferieur, se rapproche de l’âge rajeuni de la tectogenese cimmerienne. On constate Egalement que les deux zones ou des deformations eocimmeriennes importantes se sont deroulâes sont reia tiv ement paralleles. Elles sont placees sur les deux marges d’un vaste domaine continental qui s’etendait depuis la zone de Macin au Nord jusqu’aux Pontides meridionales (Anatolie du NO) au Sud. Des deux cotes de ce bloc sialique, la tectogenese eocimmerienne (rajeunie) determi- nait des raccourcissements de la croute surtout dans les zones ophioliti- feres ou assimilees. On devrait s’dtonner que, pas longtemps apres le debut du spreading (au Trias moyen) dans le paleo-ocean tethysien, des compressions (charriage de la nappe des formations permiennes — Fon r- q u i n , 1975) s’installassent! Des echos de la tectogenese eocimmerienne rajeunie14 ont ete saisis dans les Dacides orientales (y interprdtee comme phase donetz, S ă n d u - les cu, 1969, 1975). Ce sont des discordances angulaires d’importance relativement locale, de type precurseur15. On eonnaît egalement des defor- mations du meme type (precurseur) plus anciennes que le Lias. Elles sont du type discordance angulaire (monts de Brașov — Săndulescu, 1964b) et ont 6te assimilees ă la «phase» labinienne. Les evenements pre-Lias, surtout du type surrections epyrogeni- ques, sont bien marques dans la majeure pârtie du «rameau alpidique». II ne s’agit pas de vraies tectogeneses, mais d’un changement important des conditions sedimentogenes, accompagnd par des 6rosions etendues. II est saisissable surtout dans les aires ă crodte continentale ou le Trias superieur manque ou est detritique. Les zones ă croute oceanique et aminele, aussi bien que les bords de celles-ci sont immergees au Trias superieur et montrent des passages au Lias. II est interessant de remar- quer qu’une grande pârtie des Dacides occidentales montrent des carac- teres «alpidiques» dans le sens consideri ci-dessus : absence du Trias superieur ou Neotrias detritique (Keuper carpathique) et changement sedimentogenique et paleogeographique au debut du Lias. Les unites meridionales (superieures) seulement montrent des caracteres differents, marquant le rapprochement d’un domaine oceanique (qui serait situe au Sud de celles-ci et differe du domaine transylvano-piemontais — voir le chapitre sur la correlation). C’est un fait de plus pour ne pas «afri- caniser” les Dacides occidentales. Tectogeneses neoeimmeriennes. Dans la region type pour les tecto- geneses cimmeriennes — dans ce cas la Crimee — cette tectogenese est i--------------- 11 Le fait que dans la region oii une tectogendse a definic les donn6cs nouvelles changent le «timing • de celle-ci, impose la reconsid6ration de tous les endroits ou cette tec- togenese a 6te mentionn6e. Suivant le degre de pr«cision, cette reconsidâration est plus ou moins facile. II y a pourtant des zones ou l’ancienne datation reste valablc. C’est dans ce sens que nous employons le terme eocimmerienne rajeunie. 15 par j-apport â une tectogenese paroxysmale, il y a des deformations prĂcurseures et postlrumes. 3 - c. 658 < A Institutul Geological României xigr/ 34 M. SĂNDULESCU 30 placee ă la fin du Valanginien (cf. Uspenskaia, voir note infrapagi- nale 9). C’est, encore une fois, un rajeunissement par rapport ă la notion classique. Elle a un caractere paroxysmal pour la chaîne intracratonique Dobrogea septentrionale-Crhnee meridionale. Des deformations precur- seures, avec des developpements areals plus ou moins locaux de cette âge, se manifestaient dans le «rameau alpidique». Elles ne s’y sont pas gdneralisees. Une remarque generale pour la totalite de l’aire que nous analy- sons : ă la limite Jurassique / Cretace ne se produisent pas de change- ments importants, surtout pas de deformations. Aussi bien dans les series flysch, que dans celles pelagiques et neritiques carbonatees, le Tithonique et le Neocomien (Berriasien et Valanginien surtout) montrent des lithofacies communs et une sedimentogenese ininterrompue. Les tecto- geneses qu’on place «â la fin du Jurassique» s’averent presque partout. etre d’âge ante-Tithonique. Teetogenescs mesocret acces. Pour le «rameau alpidique» les tecto- geneses mesocretacees sont de premiere importance (paroxysmales) dans certaines zones de celui-lă. Elles ont determine dans ces endroits des raccourcissements de la croute d’intensites variables. Le «moment» mesocretace est place ă la fin de l’Albien. L’important changement, de vastes dimensions, qui debute au Vraconien et gagne sa plenitude au Cenomanien, suit ă ce «moment». 11 a ete pourtant precede par une agitation tectogenique remarquable, installee par endroits depuis le Barremien inferieur’, par endroits depuis l’Aptien. Ceci a doime toutes sortes de «phases», comme celle austroalpine (de Tollmann) ou celle dite de Manin (d’A n d r u s o v ), la premiere intra-Barremien ou â la limite Barremien/Aptien, la seconde au debut de l’Albien. Cette periode d’agitation tectogenique, qui groupe plusieurs phases, a culmine par celle mesocretacee (connue aussi sous le nom de phase autrichienne = Austri- che phase). Les plus importants evenements concernant les chaines peri- ponto-euxiniques lies â cette periode tectogenique et surtout au moment mesocretace sont: — les premiers charriages des nappes ă ophiolites arrivant sur le bord europeen : les plus typiques sont les nappes transylvaines, cache- tees par le Vracono-Cenomanien; — debut de cicatrisation et, par endroits, cicatrisation presque com- plete du megasillon dacique externe; — genese des nappes de socle sur le bord interne (si l’on se rapporte â la polarite de la chaîne) du megasillon, surtout dans les Dacides orien- tales (nappes centrales est-carpathiques) et une pârtie des Dacides meridionales; l’ampleur de ces charriages semble diminuer le long du « rameau alpidique» en allant de l’Ouest vers l’Est; — ecaillements et plissements (plus ou moins serres) sur la quasi- totalite des zones internes du «rameau alpidique» (lâ-ou il n’y a pas encore de charriages); 31 CHAtNES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 35 — consolidation definitive de la chaîne intracratonique Dobrogea septentrionale-Crimee meridionale. La zone dans laquelle ces deformations ne sont pas materialisees est representee par les Moldavides. Pourtant, meme lâ les echos en sont marques : l’arret temporaire de la sedimentation flysch sur la majeure pârtie de la zone et l’apparition des facies p61agiques relativement conden- ses. Dans d’autres domaines externes du «rameau» (Prebalkan, Danubien) egalement, au moins des discordances simples interrompent la sedimen- togenese. Les tectogeneses mdsocretacăes interessent en egale mesure domaines continentaux, oceaniques ou intermediaires. Pour le «rameau alpidi- que» elles representent un eiement specifique. Et on ne peut pas s’empe- cher de remarquer qu’elles soient presentes aussi dans ce domaine contro- verse qui groupe les unites Austroalpines et des Dacides occidentales. Ces tectogeneses representent l’une des premieres grandes revolutions que le domaine alpina subies. Le deuxieme grand cycle de flyschs y debute, comme par hasard, au Cretace superieur ! Tectogenese pre-Gosau. Cette tectogenese est classiquement illus- t.iee dans l’ensemble Austroalpin-Dacides occidentales. Elle y est connue aussi sous le nom de phase mediteranneenne (Tollmann, 1966). On pourrait la considerer un effet â retardement des tectogeneses m^socre- tacees. Bien que determinant des raccourcissements de la croute dans une aire relativement restreinte, la tectogenese pre-Gosau est contemporaine des changements sedimentogeniques et paleogeographiques sur des aires plus etendues. On note parmi d’autres dvenements : le debut des wild- flyschs au sommet du Turonien et au Senonien (Danubien, Prebalkan, Stara Pianina, Monts Metalliferes), discordances ă la base du Senonien precedees par des periodes d’erosion (un peu partout dans les zones inter- nes). II reste pourtant aussi des zones ou les traces de ces deformations sont minimes, la plus caracteristique dans ce sens etant, encore une fois, la zone des Moldavides. II y a aussi certains bassins sedimentaires (sur- tout â facies pelagiques) ou la sedimentation a continue tout le long du Cretace superieur. Tectogeneses îini-Cretace (tectogenese «laramienne»). Le moment tectogenique fini-Cretace est bien marque,_sur de grandes aires dans le «rameau alpidique», d’importants charriages 6tant lies â celui-ci. Ces evenements sont places vers la fin du Senonien, â la fin de celui-ci ou au debut du Paleocene. Elles sont en grandes lignes des deformations qu’on peut denommer «laramiennes», bien que la correlation interconti- nentale des evenements tectogeniques reste encore un probleme ă etudier. Le long du «rameau » on constate que, en allant des Carpathes vers les Pontides, ce moment «laramien» est de plus en plus jeune. En effet, dans les Carpathes orientales il est intra-Senonien superieur, dans la Srednegorie il est post-Maastrichtien et’ dans les Pontides â la base du Paleocene. Ce retardement progressif peut etre lie â l’achevement de 36 M. sanduuescu 32 plus en plus tardif des charriages Ie long de la chaîne, bien que, par en- droits, ils aient debute peut-etre au meme moment. La tectogenese «laramienne» est marquee aussi dans les Transyl- vanides (ou elle semble etre intra-Maastrichtien) et les Pienides, soulig- nant ainsi son grand developpement areal. II nous semble intdressant de souligner que, dans la majeure pârtie des zones affectâes par la tectogenese «laramienne», elle suit ă une periode d’activite volcanique andesitique qu’on suppose etre liee ă des phenomenes de type subduction (consommation de socles) (E ă d u 1 e s c u, Săndulescu, 1973; Grubici, 1974; Boccaletti et al., 1973 etc.). Puisqu’il precede la tectogenese, le volcanisme doit etre lie ă une deformation anterieure, pour la plupart des cas celle mesocretacee. Les tectogeneses «lăramiennes» ont achevd la eicatrisation du mega- sillon dacique externe, les nappes d’obduction qui proviennent de celui-ci etant cachetees (lă-ou des couvertures post-nappe ont ete conservees) par des formations paleogenes. La eicatrisation des Transylvanides est egalement achevee par cette tectogenese, surtout du cote des Monts Metalliferes. Les Moldavides restent l’endroit ou les tectogeneses «laramiennes» ne sont pas presentes par des deformations. Elles s’y refletent pourtant par des changcments sedimentogenes qui se traduisent, semble-t-il, par le rajeunissement du relief de certaines cordilleres, d’une part (couches d’Istebna liees ă la cordillere silesienne-Carpathes occidentales), ou par une diminution de la subdsidence flysch (flyschs paleocenes d’epaisseurs comparativement reduites), de l’autre part. Apres le moment «laraxnien», Ies premieres grandes intrusions alpi- nes ont ete mises en place: lesintrusionsbanatitiques. Elles sont pour la majeure pârtie (des Carpathes et du Balkan au moins) paleocenes (âventuel- lement de l’Eocene inferieur). II n’est pas exclu que par endroits elles aient eommence plus tot (E u s s o- 8 ă n d u 1 e s c u et Vi j d e a , donnees inedites). Tectogeneses post-Lutenien (pyrâneennes). Dans le Balkan externe et les Pontides des deformations post-Lutetien et anțe-Priabonien (?) ont eu lieu. Elles ont ete precedees par des flyschs. Ces tectogeneses n’ont pas laisse de traces dans les Carpathes, du des deformations de cet âge etaient inconnues. II semble que la distribution areale des deformations pyreneennes ait une liaison avec la eicatrisation definitive des zones ophioiitiferes du «rameau dinarique» (Aubouin, 1973), l’arrivee d’une collision con- tinentale donnant des echos sur le bord europeen. Ce n’est pas une chaîne detype back-arc (Boccaletti et al., 1974) dans son sens classique, mais simplement la «reponse» d’une zone ayant gardee une certaine mobilite ă une compression importante subie par une zone voisine et parallele. Le volcanisme et les intrusions connues dans le Ehodope sont conse- quentes ă cette tectogenese. Par rapport â celles senomennes et paleo- 33 CHAINES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 37 cenes, elles seraient liees ă une autre zone de consommation de socle de type subduction. En effet, si les plus âgdes etaient considerees liees ă la cicatrice du megasillon dacique externe, les secondes seraient liees ă celle dinaro-hellenique. La distribution areale relativement restreinte des tectogeneses pyre- neennes — dans le secteur que nous analysons — et leur caractere subor- donne aux grandes tectogeneses du «rameau dinarjque» montrent qu’ă ce moment l’avant-pays europeen n’a pas joue role de moteur, celui-ci revenant ă l’avant-pays africain. Tectogenese intra-Miocene inferieur. Bien que la tectogenese sa vi en- ne ait ete classiquement consideree ă la limite Oligocene/Miocene, des recherches stratigraphiques plus ou moins recentes ont montre que les plus jeuneș formations precedant les charriages de cet âge des nappes du flysch moldavien n’etaient pas exclusivement oligocenes, mais mon- taient aussi au Miocene inferieur (Martini, Lebenson, 1971.; Ș t e f ă n e s c u et al., 1979). En remarquant que ce moment est intra- Miocene inferieur, Dumitrescu et Săndulescu (1968) Font assimile ă la phase styrienne ancienne, se rapportant toujours au tableau classique des phases des tectogeneses alpines. On a donc ă choisir entre le nom de tectogenese savienne rajeunie (dans le meme sens que pour celle cimmerienne rajeunie — voir plus haut) ou de tectogenese styrienne ancienne, ou bien de tectogenese intra-Miocdne inferieur, pour1 rester dans un cadre plus gendral. La tectogenese intra-Miocene inferieur a essentiellement affecte la zone du flysch des Carpathes : aussi bien les flyschs des Moldavides, que les flyschs des Pienides, pour ces dernieres unites representant la deuxieme phase paroxysmale (voir chapitre Carpathes). Elle a genere des nappes de couverture constituees de formations flysch, cretacecs et paleogenes pom1 la plupart. Le raccourcissement de la croiite doit etre considere assez important, tenant compte du fait que ces nappes sont entierement d6collees de leur substratum et deplacees vers et aussi au-des- sus' de l’avant-pays. Le raccourcissement de la croute pour les nappes d’âge intra-Mio- cene inferieur, aussi bien dans les Moldavides que dans les Pienides, suppose la consommation de socles sialiques, du moins une pârtie des anciens soubassements des bassins sedimentaires du flysch. Les compressions intra-Miocene inferieur ont eu aussi des «reflets» dans les zones deja tectonisees et plus ou moins rigidisees, non plus par charriages, mais par fracturations, parmi lesquelles certaines de type faille inverse. II s’agit aussi bien de retroplis ou retrochevauchements, que de deformations ă vergence conforme ă celle generale de la chaîne. Dans les Kraijstides, sur le front de la nappe de Șasea-Gornjak, dans le graben de Petroșani, dans la zone cristallino-mdsozoîque des Carpathes orientales etc., ces deformations post-tectoniques (posthumes) sont bien materialisees et ont des formes et des intensifes differentes. Ce n’est pas seulement la tectogenese intra-Miocene inferieur qui soit accompagnee — dans les aires tectonisees plutot — par des d^forma- Institutul Geological României 38 M. SĂNDULESCU 34 tions posthumes. Celle «laramienne» a eu des effets semblables. Mais, on constate qu’au four et ă mesure que la tectogenese est plus jeune, les deformations connexes sont mieux saisissables, peut-etre puisque les zones ddjă rigidis6es etaient de plus en plus larges. Aux tectogeneses intra-Miocene inf6rieur font suite, dans les Car- pathes, d’importantes manifestations volcaniques, surtout andesitiques (R ă d u 1 e s c u , B o r c o ș , 1968). La reprise des processus de consom- mation de socles, dont une pârtie de type sialique, est directement liee â cette activite et â ses particular it6s geochimiques (R ă d u 1 e s c u, Săndulescu, 1973). Tectogenese inlra-Badenien et tectogenese intra-Șarm a tien (mol- dave). Les deux dernieres tectogeneses responsables de charriages sur le bord externe des Carpathes sont plutot les deux maximums d’une seule periode tectogenique, qui ddbute apres le Langhien et finit au Bessara- bien (en grandes lignes au Tortonien tethysien). L’avant-pays a subi ces derniers sous-charriages gdneralises sur la majeure pârtie du front car- pathique. Apres la tectogenese moldave (intra-Sarmatien)16 s’installe ă la peripherie des Carpathes la grande depression molassique sar- mato-pliocene assymetrique, qui est l’avant-fosse externe ou epicra- tonique (D u m i t r e s c u , Săndulescu, 1968). Les molasses qui s’y trouvent recoivent surtout du materiei provenant de la chaîne carpathique (des molasses plus anciennes sont riches en detritus pro- venant de l’avant-pays). Comme la tectogenese intra-Miocene inferieur, celles intra-Badenien et intra-Sarmatien sont limitees aux Carpathes. Par ailleurs, des fractu- rations, plissements larges ou bombements sont connus, en tout cas pas de deformations engendrant des raccourcissements de la croite (il s’agit, bien sdr, de la region analysee dans cette note). Tectogenese valaque. Ă la fin du Pliocene ou dans le Pleistocene inferieur des plissements loealises ă la courbure des Carpathes orientales ont defini la phase valaque. II s’agit de plis verticaux ou deverses, par endroits seulement de plis-failles, auxquels sont associds des processus de diapirisme (le diapirisme a ete defini dans cette region). Les plis issus de la tectogenese valaque sont loealises dans une region qui «regarde» vers un panneau de l’avant-pays, mobile jusqu’aux plus jeunes moments de l’evolution des Carpathes. Limite par les failles de Peceneaga-Camena au Nord et par la faille intramoesienne au Sud, ce panneau a determine par son mouvement vers les Carpathes (R ă d u 1 e s c u et al., 1976) le plissement valaque. La sismicite de la region de Vrancea n’est pas sans liaison avec les translations du panneau de l’avant-pays raentione. 1 8 St i 11 c (1953) a defini la phase moldave responsable des derniers charriages affec- tant le bord carpathique. II Ies considerau, â ce moment, situes a la limite «Tortonien» (actnel Bad£nien)/Sarmatien. II a 6te precist que cette phase est intra-Sarmatien (D u mi- tre s c u, S ă n d u 1 e s c u, 1968). Institutul Geological României (GR 7 35 CHAINES ALPINES AUTOUR DE LA MER NOIRE OCCIDENTALE 39 L’analyse du deroulement des tectogeneses, de leur âge et de leur distribution areale nous condu it â quelqu.es conclusions gdn6rales que nous synthetiserons ci-dessous : — les tectogeneses cretacees sont plus repandues que celles miocenes; peut-etre que la mobilite de la croute etait plus accusee, vu que les paleo- zones oceaniques ou ă croute amincie ne s’etaient pas encore cicatrisees entierement; — la forme, l’intensite et l’extension areale d’une tectogenese sont variables d’un moment ă l’autre; — chaque groupe d’unit^s est caracterise par une (soit deux, mais pas tres frequemment) tectogenese principale qui a determine le transport tectonique et le raccourcissement de la croute les plus accuses : de la, l’isochronisme de la tectogenese principale au sein du meme groupe et le heterochronisme d’un groupe ă l’autre; — dans le «rameau alpidique» il y a deux periodes principales d’agitation tectogenique, periodes qui groupent plusieurs phases ou moments : une cretacee (de l’Albien et meme du Barremien jusqu’au Maastrichtien), une autre miocene (du Burdigalien jusqu’au Bessarabien); la phase pyrencienne y est plutot un reflet sans participation active de l’avant-pays europeen; — la polarite orogenique existe sui' certains segments du «rameau alpidique»; il y a d’autres qui ne repondent pas â cette loi; pourtant, si l’on envisage les periodes tectogeniques seulement (et non pas les phases individuelles), la polarite est plus marquee; — la duree des deux periodes tectogeniques est bien differente; 35 m.a. (Albien-Maastrichtien) pour celle cretacee, 8—10 m.a. pour celle miocene; — la frequence des phases est plus grande au Miocene (tous les 3—5 m.a) qu’au Cretace (5 — 10 m.a.). HYPOTHÎJSE D’EVOLUTIOX GEODYNAMIQUE Tout modele evolutif doit partir d’un modele structural. Les incer- titudes concernant ce dernier se retrouvent for cement dans l’etablisse- ment du premier. Tout eloignement des realit&s structurales, surtout des connexions etablies sur des faits controles, entraîne les modeles evolutifs ă. des conclusions risqu6es et souvent inexactes. Les dernieres analyses sur l’evohition de tout l’ensemble que nous envisageons dans cette note ou seulement sur des segments de celui-ci tiennent compte des principes de la nouvelle tectonique globale. C’est sur les Carpathes surtout que ces analyses se sont penchees, oii l’exis- tence de plusieurs arcs volcaniques et de plusieurs oicatrices ophiolitiques a vait incite les auteurs â faire des comparaisons avec les modeles de la tectonique des plaques. Nous allons faire un tres bref aperșu sur les differentes contributions concernant d’abord les Carpathes, ensuite les autres secteurs et aussi l’ensemble periponto-euxinique. 40 M. SĂNDULiESCU 36 Pour les travaux concernant les Carpathes, on peut distinguer deux groupes : (1) ceux qui ont voulu trouver dans les Carpathes un modele identique â celui 61abor6 pour les oceans actuels et (2) ceux qui ont retenus des principe» de la tectonique des plaques, les donnees qui s’accordent avec celles structurale». Pour la grande majorite des auteurs, l’existence de la chaîne volca- nique neogene a ete un point de depart pour l’elaboration de leurs modeles, en acceptant sa genese liee a une paleozone de consommation (de socles). La position de cette paleozone est illustree sur des coupes dans un nombre restreint de travaux. Pour certains (Rădulescu, Săndulescu, 1973; Rădulescu et al., 1976), elle correspond ă la zone de consommation de socles des flyschs est-carpathiques, pour d’autres elle est situee sous l’avant-fosse carpathique (R o m a n, 1970 ; C o n s t a n t i n e s cu et al., 1973, 1975), liee ă la zone sismique de Vrancea. Dans le premier cas, on envisage l’engloutissement des socles de type oceanique et sialique, dans le second, de la lithosphere continentale ou bien seulement l’existence des «courants descendants de subduction» (qui n’entraînent pas de lithosphere? !). La presence des socles de type sialique sous les nappes du flysch (prouvee par forages ou par geophy- sique), le caractere de nappe de couverture des unites du flysch, la position de Parc volcanique sont des argument» pour soutenir la premiere hypo- these mentionnee ci-dessus. Une deuxieme paleozone de consommation a ete envisagee (R ă d u 1 e s c u , Săndulescu, 1973 ; pro parte, B 1 e a h u, 1974) sous la depression de Transylvanie et les Monts Apuseni, marquee par des restes de croute de type oceanique (ophiolites). Elle a ete confirmee pai' des travaux geologiques et geophysiques recents (R ă d u 1 e s c u et al., 1976; Săndulescu, Visări o n, 1978; Vis ar ion, S ă n d u 1 e s c u , 1979). Lie a cette deuxieme palâozone de consomma- tion, il faut mentionner aussi d’autres hypotheses concernant le scubasse- ment de la depression de Transylvanie. Cherchant une similitude avec les arcs insulaires, certains auteurs (Bleahu et al., 1973; Bleahu, 1974 ; B o c c a 1 e 11 i et al., 1974 ; Mor el li et al., 1976) ont assi- mile la depression dc Transylvanie avec un «back-arc basin». Ils admettent un «spreading» tertiaire dans son soubassement (aussi bien que dans celui de la depression pannonienne). L’etat actuel des connaissances sur la structure du soubassement de la depression de Transylvanie (C i u p a g e a et al., 1970 ; Rădulescu et al., 1976 ; S ă n d u 1 e s c u, V i s a r i o n, 1979) permet de prâciser qu’il est constitue d’unites â tectogenese ce- tacee (de compression !) pour la majeure pârtie, etant le prolongement de celles qui affleurent sur les bords de celle-ci. Les ophiolites qui s’y trou- v Geochimic and Genetic Study of the Olphiolites in Niculițel Zone. D.S. Inst. geol, LXV, 1, București. Săndulescu M. (1964a) Les couches de Sinaia ct les couches de Bistra entre Răchitiș et Izvorul Ciobănașului. D.S. Com. Geol-, (1962—1963), 2, 371 — 382, București. — (1964b) Structure geologique du massif de Postăvaru-Runcu (monts de Brașov). An. Com. Geol., XXXIV, 2, 381-432. București. — (1969) Structura geologică a părții centrale a sinclinalului Hăghimaș. D.S. Inst. geol. LIV, 3, (1966-1967), 227, 263, București. — (1967a) La structure geologique des terrains mesozoîques de l’exterieur du massif cris- tallin de Făgăraș. D.S. Com. geol., LII, 2 (1964 — 1965), 177—208, București. — (1967b) La nappe de Hăghimaș, une nouvelle nappe de decollement dans les Carpathes Orientales. Assoc. Carp.-Balc., VIII Congr., I, 179—185, Belgrad. — (1972) Considerații asupra posibilităților de corelare a structurii Carpaților orientali și occidentali. D.S. Inst. geol-, LVIII, 5, 125—150, București. — (1973) Essai de reconstruction des elements preparoxysmaux alpins des Dacides (Inter- nides) orientales. Rev. geol-, heogr., geophys., ser. gel., 17, 1, 145 — 156, București. — , (1975a) Studiul geologic al părții centrale și nordice a sinclinalului Hăghimaș. An. Inst. geol. geofiz., XLV, 200 p, București. — (1975b) Essai de synthese structurale des Carpathes. B.S.G.F (7), XVII/3, 299—358, Paris. — .(1976) La corr61ation structurale du troncon oriental avec celui meridional des Carpa- thes roumaines. D.S. Inst. geol. geofiz., LXII/5, București. — Micu M., Pop eseu B. (1977) La structure et la palăogăographie des formations miocenes des Subcarpathes moldaves. XI Congr. Ass. Geol. Carp. Balk., Kiew (ră- sumes). 54 M. SĂNDULESCU 50 — (1978) The Moesian Platform and the North Dobrogea Orogene. Geol. Atlas Alpine Europe. Elsevier, 427—442. — Visa r ion M. (1978) Consid6rations sur la structure tectonique du soubassement de la depression de Transylvanie. D.S. Inst. geol. geofiz., LXIV, 5, 153—173, București — (1980) Sur certains problâmes de la correlation des Carpathes Orientales roumaines avec les Carpathes ucrainiennes. D.S. Inși. geol. geofiz., LXV, 5, București. Schatalov G. (1958) Uber die Straligraphie, Lithologie und Mctamorphismus des Juras im Ostlichen Strandjagebirge. An. Dir. gen. Res. gtol. ser. A, 8, 27 — 76, Sofia. — (1967) Stratigrafia na Jurata v centralnaia Strandja Pianina. Bull. Geol. Inst., ser. geotect., straligr., lithol., XVI, 145 — 166. — B u du r o v I., S t cf a n o v S. A. (1972) Uber Petrographic und ConodontenKarni- scher Kalke aus dem Gebiet des Dorfes Gramatîkovo Strandjagebirge. C.R. Acad, bulg. Sci., 25, 11, 1549, 1552, Sofia. S i k o s e k B., Maxim ovici B. (1966) Essai de I’origine de l’histoire structurale de la Serbie orientale entre le Danube et le Timoc. Bull. Mus. d’Hisl. Nat. Paris, ser. A, 19—20, Paris. St iile H. (1953) Der geotektonische Werdegang der Karpaten. Berii, fur Geol. Jb., 8, 239 p. Ștefănescu M. (1973) Efectele mișcărilor intrancocomiene în partea internă a flișului eocretacic de Ia curbura Carpaților. St. cerc. geol. geofiz., geogr., ser. geol., 18, 2. 469 — 477. București. — (1976) O nouă imaginea structurii flișului intern din regiunea de curbură a Carpaților, D.S. Inst, geol. geofiz., LXII, 5, 257 — 259, București. — (1978) Stratigrafia și structura flișului cretacic și paleogen dintre valea Prahovei și valea lalomiței. Teză de doctorat. Univ. București. — Gheța N., Dicea M. (1979) On the Oligocene-Miocene Boundary in the Exter- nai Flysch Zone of the Garpathian Bend (between the Teleajen Valley and the Dîm- bovița Valley). A Tentative Solving by Calcareous Nannoplankton. Ren. roum. geol. geophys. geogr., ser. geol., 23, 1, 89—94, București. Tollmann A. (1965) Das Strandscha-Fenster, ein neues Fenster der Metamorphiden im alpinen Nordstamm der Balkan. N.Jb. Geol. Pal. Min., 4, 234—248. — (1966) Die alpidischen Gebirgsbildungs-Phasen in den Ostalpen und Westkarpathen. Geolekt. Porsch., 21, 1 — 156, Sluttgart. T r ii m p y R. (1975) Penninic-Austroalpine Boundary in the Swiss Alps : A Presumcd For- mer Continental Margin and Its Problems. Am. Jour. Sci.. 275-A, 209—238. V i s a r i o n M., Săndulescu M. (1979) Structura subasmcntului depresiunii pannonice în România (sectorul central și sudic). St. cerc, geol, geofiz., geogr., ser. geofiz., 17, 2, 191 — 201, București. W a 11 h er H. J. (1974) Crystalline Regions of North-Eastern Greece. In : Tectonics of the Carpathian Balkan Regions, Geol. Inst. D. Stur. 297—301, Bratislava. Wilsner .1. L. (1928) Die geotektonische Stellung des Kaukasus und dessen Bcziehungen zu Europa. Z. deutsch. Geol. Ges., 80, 153 — 194, Stuttgart. Institutul Geological României Project 39 : Ophiolites of Continents and Comparable Oceanic Rocks GENESIS OF THE ALPINE CYCLE OPHIOLITES FROM ROMANIA AND THEIR ASSOCIATED CALC-ALKALINE AND ALKALINE VOLCANICS1 BY H. SAVU2 Ophiolites. Inilialites (inițial magmatism). Alpine tectonics. Pelrogenesis. Calc-alkaline volcanism. Alkaline volcanism. Oceanic zones (ocean floor). Ocean floor basalts. Tethys zone. Island arc; East Carpathians. South Carpathians. Apuseni Mountains. Norlh Dobrogea. Sommaire Genese des ophiolites du cycle alpin de Rou manie et des initialites c h a 1 c o-a leali nes et a 1 c a 1 i n e s associCes. Les ophiolites ct les autres initialites alpines de Roumanie se trouvent : 1) en position autochtone (zone de Mureș), 2) en nappes de charriage, 3) en klippes, 4) en zones d’obduction (Dobrogea). A Fencontre de la zone typique des Alpes-Himalaya, le inagmatisme inițial — prăorogene — — des zones oceaniques etroites au nord de la Mer TCthys a produit surtout des roches effusivcs et extrusives. Les structures stratifiees des corps de gabbros et ceux ultrabasiques aussi que le mCtamorphisme dans la zone de contact des basaltes constituent les preuves pâremptoires que ces corps-lă representent des intrusions de magma tholeiitique provenu du manteau qui se sont differenciees in situ. La structure stratifice typique des ophiolites de Grece et de Chypre n’a pas ete mise en evidence dans les zones carpathiques, ce qui mene â la conclusion que les trois membres d’une sCrie ophiolitique (pCridotite-gabbro-basalte) se trouvent non seulement dans une situation de superposition, mais aussi dans des relations d’intrusion. Les zones oceaniques au nord de la Mer Tdthys se distinguent des zones typiques par la quantite rCduite de roches ultrabasiques et par la presence des initialites chalco-al- calines et alcalines des ares insulaires qui font defaut des zones typiques. Dans la zone du Mureș on rencontrc le passage du stade de zone aux ophiolites de fond oceanique au stade de zone volcanique d’arc insulaire preorogdne. L’activitC magmatique s’est devclopCe dans 1 Paper received on November 14, 1979 and acccptcd for publication on March 11, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. 56 H. SAVU 2 des zones oceaniques â fond simatique ou simatique et sialique a la fois. I.es roches ophioli- tiques ont les caracteres de basaltes de fond oceanique â l'exception de quelques-unes qui sont des magmatites d’îles oceaniques de type intraplaque; les initialites chalco-alcalines et alcalines — en peu nombre — associees aux ophiolites reprâsentent des volcanites dare insulaire preorogene ou sous-marin et se sont fonnees durant la m6me etape preorogene des zones oceaniques alpines oii seuiement les roches ophiolitiques se forment dans les zones typiques. II s’ensuit que dans les zones oceaniques du domaine de la Mer Tethys, selon la structure et les conditions particulieres d’evolution, les roches ophiolitiques — des formations de fond oceanique ou de plaque oceanique — apparaissent dans des situations differentes. Autrement dit, 11 y a ophiolites et ophiolites tout comme il y a « granites et granites ». Introduelion Remarkable progress has been made in the study of the present and fossil oceanic zones in the past ten years, by the comparison of the most characteristic geological formations — the ophiolitic rocks — that form in the spreading stage of the oceanic floor. The term ”ophiolith”, an old denomination for the serpentinitic rocks in the Alps, was introduced in Science by B r o n g n i a r t in 1813 ; since then it has been adopted by all geologists, gradually becoming ever more comprehensive. Thus, Steinmann (1927) extends this notion lending it a funcțional meaning, as it included all the ultramafic (serpentinites, peridotites) and basic rocks (gabbros, diabases and spili- tes) that form together in the eogeosyncline stage. Later S t i 11 e (1940) finds that in the primary or pre-orogen stage of the geosyncline there develops an inițial magmatism with rocks of sima tic na ture. He uses the term ”ophiolite” only for the ultramafic rocks; still he attributes the denomination of inițial magmatites to the whole group of basic and ultramafic rocks that form at the beginning of a tec tono-magma tic cycle. In the study on the petrochemistry of the ophiolites from the Alps, Apen- nines and Dinarides, published in 1945, Burri and Niggli mea ut by this term all the Alpine inițial magmatites that appear in the eogeo- syncline stage. In recent years, as the plate tectonics theory developed, a new conception was worked out concerning the genesis of ophiolites, which determined a rapid development of researches on these rocks from the tectonic, petrologie, geochemical and metallogenic point of view. At present the ophiolite genesis is regarded as a much more complex process, in which these rocks represent only the oceanic crust, formed in the median ridges, whence it migrates by the spreading of the ocean floor towards the margins of continents and is then subducted in the mantie and possibly obducted on the continent (Co Ierna n, 1977). Usually an ophiolitic complex is considered to show a layered structure with ultramafic rocks in the base, overlain by gabbros, dole- rites in sheeted dykes and basalts in pillow lava facies that underlie Institutul Geological României 3 GENESIS OF THE ALPINE OPHIOLITES FROM ROMANIA 57 jaspers, as in the ophiolitic complexes from Greece and Cyprus (Brun n, 1956 ; A u b o i n, 1959 ; M o o r e s , 1969). In spițe of this classic defi- nition, there are also different situations as will be further seen in this paper. Important researches have been also carried out in the past three decades on the ophiolites from the Carpathian domain, significant results being obtained. As the Alpine ophiolitic rocks from the Carpathians show several peculiarities in comparison with those belonging to other regions. they will be described in the paper together with the other Mesozoic initialites, with which they associate and form characteristic magmatic complexes. Oceanic Zones of the Alpine Cycle on the Romanian Territory Two geosyncline (Savu, 1968) or oceanic zones (Bădulescu, S ă n d u 1 e s c u , 1973) were considered to have functioned on the Boma- nian territory during the Alpine cycle. Now we think there were three such Alpine zones in which inițial magmatites formed (Fig. 1) : (1) two Carpathian zones with a branch that passcd through North Dobrogea; the oceanic zone stage manifested in two Alpine epochs only in the East Carpathians; (2) the Mureș zone from the South Apuseni. The geological history of this territory, situated in the northern part of the Tethyan Sea, on the south-western margin of the old East European continent, is much older. The post-Carelian evolution of this part of Europe began at the end of the Middle Precambrian, about 1600 m.y. ago, on a primordial (?) oceanic zone in the Carpathian domain as well as in an intracontinental rift zone in North Dobrogea and continued during the subsequent tectono-magmatic cycles, namely Dalslandian. Assvntic, Hercvnian (Caledonian) and Alpine (Giușcă et al., 1969). After the formation in the Dalslandian cycle of a first sialic crust, that joins the margin of the East European continent, it breaks at the beginning of each following cycle, while new oceanic zones, parallel to the margins of the old continent, regenerate. This is demonstrated by the fact that the folded structures in the crystalline schists from the first three or four cycles as well as those from the Upper Paleozoic and Alpine sedimentary deposits overlap in the same zones and are parallel to one another. Such structures are found both in the Carpathians, the Apuseni Mountains and in North Dobrogea. Ophiolitic rocks as well as other inițial magmatites form in each cycle; they are now in different metamorphic stages. These rocks appear in the form of orthoamphibolite complexes or albite green schists (meta- basalts. metaspilites, metadolerites, metagabbros) and small size lenticular bodies of peridotites, Iherzolites, saxonites, wehrlites, harzburgites, dunites and serpentinites, intercalated in the metamorphosed terrigenous forma- tions (Savu et al., 1977) from the Carpathians, the Apuseni Mountains and Dobrogea. 58 H. savu 4 At the end of the Hercynian movements, the Paleozoic oceanic zones had closed again, while a new sialic crust formed in the Carpathian domain of the Tethyan Sea; during the Permian and at the beginning of the Triassie, an epicontinental sedimentation manifests on the sialic crust. The Alpine geotectonic evolution of the Romanian territory started simultaneously with the beginning of the migration of the continental Fig. 1. — Sketch of the oceanic zones and tectonic piates of the Carpathian domain at the beginning of the Mesozoic : EEP, the East European plate : PMp, Pannonian inicroplate : AMMp, Apuseni Mountains microplatc ; TMp, Transylvanian inicroplate; MMp, Moesian micro- plate ; 1, Triassie oceanic zone ; 2, Carpathian oceanic zone : 3, Mureș oceanic zone (South Apu- seni) ; the arrows indicate the sinking direction of the piates. piates. The floor of the northern part of the Tethyan Sea, together with the sialic crust, is broken into severa! piates or microcontinents, separatei! among them by oceanic zones, in which ophiolitic rocks and other initia- lites form (Radul eseu, Săndulescu, 1973; Herz, Savu, 1974; Bleahu, 1974; Savu, in pressd). The following stages can be distinguished during this evolution : 3 Savu II. (1980) Ophiolitic Rocks and Inițial Magmatites in the Carpathians (in press). Institutul Geologic al României 5 GENESIS OF THE ALPINE OPHIOLITES FROM ROMANIA 59 1. The formation of a deep fractura, which generates a first Meso- zoic oceanic zone by crust spreading — the Șiret Ocean (H er z , S a v u, 1974) — situated between the East European continental plate to the east and the Moesian and Transylvanian microplates to the west and south-west (Fig. 1). This oceanic zone extended along the margin of the old East European continent from the East Carpathians towards NW, through the West Carpathians and towards SE and ESE through the oceanic zone of North Dobrogea, towards the Crimea and the Caucasus (S a v u et al., 1980). Although Triassic sedimentary deposits, widespread in the Moneasa- Vașcău plateau, formed in the Auseni Mountains during this period, there are no data attesting the existence of a Triassic oceanic zone with ophiolitic rocks in this region too. Triassic ophiolitic rocks are also un- known in the South Carpathians. In the Șiret Ocean there develops an oceanic crust with ophiolitic rocks. represented by diabases, gabbros and ultrabasites associated with oceanic sediments, that are known from the West Carpathians to the East Carpathians and North Dobrogea. 2. In the Upper Triassic, when the old Kimmerian movements manifest, an underthrusting (“subduction”) process of the East European continent under the Transylvanian and Moesian plates takes place, accom- pauied by the obduction of the diabase-spilitic rocks from North Dobrogea, which were folded together with the associated limestones and pushed to NE, facing the East European continent, and probably by the con- sumption of a part of the ophiolites from the Șiret Ocean (East Carpa- thians). After these movements, the oceanic zone of North Dobrogea closes irrevocably, the Moesian plate joining again the East European plate and making up together a unitary platform. 3. Immediately after the old Kimmerian movements, at the end of the Triassic or the beginning of the Jurassic, a new phase of break- ing the sialic basement of the Tethyan Sea from the Carpathian domain begins, this time with the formation of two oceanic zones, approxima- tely parallel to one another. One of these was situated along the present principal Carpathian chain: it extended from the West Carpathians, through the East Car- pathians to the South Carpathians and continues in the Balkans. It was situated between the Transylvanian plate to NW and the East European- Moesian continent outside (Fig. 1). As can be seen, this zone does no longer communicate with the mobile zone of North Dobrogea which had closed irrevocably. On the contrary, this new oceanic zone crosses the old Triassic zone in the Carpathian bend area, breaking the link between the North Dobrogea segment on the one hand and the Transylvanian or East Carpathian one on the other hand. The second oceanic zone that forms now is the Mureș zone from the South Apuseni, situated between the Transylvanian sialic plate and that of the North Apuseni, and the East Pannonian one that was part of the Dinarides at that time (II e r z and S a v u , 1974). This oceanic zone continues towards SW, Institutul Geological României igrZ 60 H. SAVU 6 being connected with the large Vardar ophiolitic zone. The most impor- tant mass of ophiolitic rocks from Romania, comprised between the Lower Jurassic and Oxfordian, forms in the period of spreading of this zone. The radiometric age of the ophiolites from this zone is 180 m.y. (Herz et al., 1974), which indicates that they started forming sinc-e the Lower Jurassic. 4. The closing of these zones takes place gradually. It begins for instance in the Mureș zone, with the new Kimmerian movements and ends with the Austrian movements through a weak bilateral subduction or collision process of the sialic plates under the Mureș mobile zone from the Apuseni Mountains (Savu, Constanța Udrescu, 1973 ; Savu, 1976). The East Carpathians zone begins to close with. the Meso-Cretaceous movements, by a westward subduction process (R â d u- 1 e s c u, Săndulescu, 1973), but it continues also during the Ter- tiary. Throughout this long closing period of the oceanic zones. lasting from the Upper Jurassic to the Aptian-Albian (140 m.y. — 120 m.y.), Mesozoic initialites showing a calc-alkaline and alkaline character form in both zones. The Oeeurrence of Ihe Ophiolitic Rock Complexes and oî Their Associated Initialites Due to the extremely complicated tectonies of the Carpathian chains, and especially of the East Carpathians and South Carpathians, it is often impossible to establish the origin zone of the ophiolitic rocks and their associated initialites. These formations usually show allochtho- nous positions and are often includeți in the Wildflysch formations. as in the East Carpathians (P a t r u 1 i u s et al., 1966 ; S ă n d u 1 e s c u, 1976 b) and the Apuseni Mountains or make up melange formations like those from the South Carpathians (Savu et al., 1978 b). Although the ophiolitic rocks and the other Mesozoic initialites formed in two distinct stages, one eannot state precisely which rocks formed in the Triassic oceanic zone or in the Jurassic-Lower Cretaceous one because of the oeeurrence conditions and the lack of radiometric age data. That is why all the rocks in this region will be presented together. 1. The Ophiolites and Associated Initialites from the East Carpathians and North Dobrogea. The ophiolites make up a complex associated with the black flysch in the northern extremity of the East Carpathians (Bleahu, 1955)4. This complex is tectonically situated between the crystalline schists of the Bucovinian nappe and the Sinaia-Rahov flysch. They are represented by diabasic rocks with porphyric texture and often fluidal structure within which one can distinguish basalts, plagiobasalts and amygdaloidal basalts, lavas with which pyroclastics associate, pala- gonite glasses and rocks with hypabyssal characteristics, such as dolerites, porphyric dolerites and spilites formed of plagioclase (An5) and a violet 4 Arch. I. G. G., București. Institutul Geological României 7 GENESIS OF THE ALPINE OPHIOLITES FROM ROMANIA 61 titanaugite. The clinopyroxene resembles very much the titanaugite: from the Triassic diabase-spilites of North Dobrogea (Sav u et al., 1980). The basic rocks are associated with the Mihailec and Vîrtop volcano-sedi- mentary formations with stromatitic character, formed of alternations of limestones, argillites and basic lava flows and respectively limestones impregnated with chlorite and sericite. The basic rocks are supposed to be of Lower Cretaceous age, but some researchers think they may be even older. Ophiolitic rocks intercalated in the Sinaia-Rahov beds, belonging to the Ceahlău west-internal nappe, were pointed out by M a rinesc u (1979)5 in Bucovina, without mentioning whether they are in situ. klip- pes or olistolites. The ultramafic rocks are represented by serpentiniza- ted peridotites, some of them with kămmererite. The above-mentioned author also points to the presence of the basic rocks in the crystalline schists of the Bucovinian nappe. in which there lie also Triassic dolomites. Southwards, along the East Carpathians, Triassic, Jurassic and Lower Cretaceous diabases (M u r g e a n u , Pat r u lins, 1960) asso- ciated with the sedimentary deposits from the marginal synclines of the Crystalline-Mesozoic zones as well as of the Cretaceous flysch in the vicinity of the contact with the crystalline schist zone. Krâutner (1931) points to the presence of the diabasic rocks associated with radiolarites in the Lower Cretaceous, in the Rarău- Hăghimaș syncline. These rocks are represented by spilites (Sa vu, 1968' and serpentinites, whose age may be Lower Cretaceous (M u t i - hac, 1965) or/and Triassic-Ladinian (Patrulius, 1960). S ă n d u - 1 e s cu (1976 a) States that the ophiolites from this syncline are gene- rally in an allochthonous position, being inchided as Idippes in the Eocveta- ceous Wildflysch formation or being part of the Transylvanian nappes. Recently, Săndulescu-Russo et al. (in press)6 have shown that in the outliers of the Transylvanian nappes, there are peridotites, Iherzolites, harzburgites, wehrlites, websterites and serpentinites. at the expense of which listwânites and ophicalcites form. The basic rocks (spilites, \ >rio- lites, amygdaloidal spilites, dolerites, albite dolerites) and granophyres. as well as the basic tuffs and tuffites associated with jaspers, form most of the mentioncd klippes. Some authors (P a t r u 1 i u s et al., 1966 ; S ă n d u- lescu, .1976) think that the ophiolitesfromthe Hăghimaș-Rarău mar- ginal syncline and Persani come from a zone situated now under the Transylvanian Depression. This idea does not differ very much from our conclusions, but we think that this zone cannot be the same as the Mureș zone, in which no Triassic ophiolites are known. 5 Mar in eseu I. (1979) Flișul de Corbii din Bucovina, Carpații Orientali (in press.} 6 Săndulescu-Russo Doina, Udrescu Constanța, Medeșan Alexandrina (1979) Caracterele petrochimice ale ofiolitelor mezozoice din sinclinalul marginal Rarău-Hăghimaș (in press). Institutul Geological României 62 H. SAVU 8 We also note the presence of a small body of gabbro-dolerites Cros- sing the crystalline schists east of lacobeni (Pi tul ea, Mușat, 1965). The rock is formed of plagioclase (An80), diallage and hypersthene. In the Perșani Mountains there are Mesozoic inițial magmatites that formed from the Triassic to the Lower Cretaceous. In the Codlea basin from the Southern part of the East Carpathians, as well as in the north-eastern extremity of the Făgăraș Mountains the Mesozoic volcanics are of Liassic age. C i o f 1 i c a et al. (1965) showed that, in the Perșani Mountains, the first phase of the Mesozoic inițial magmatism manifested from the Middle Triassic to the Upper Triassic. The magmatites associate with limestones and occur as outliers that cover tectonically the Barremian- Aptian Wildflysch, or in the form of olistolites included in it. The origin place of these allochthonous iniatialites would be the Triassic oceanic zone that functioned also on the present place of the East Carpathians, that is the ophiolitie suture which closed in the Upper Triassic, from which the ophiolitie rocks and their associated initialites came. The magmatic activity begins at the end of the Ladinian with ophitic basalts and spilites, more rarely amygdaloidal rocks in pillow lava facies. They are associated with serpentinites, peridotites, gabbros and gabbrodolerites. The gabbroic rocks consist of bytownite plagioclase, which is saussuritizated here and there, and uralitizated diopside, or replaced by actinolite. There follow eruptions of calc-alkaline initialites with oligophyres and andesites, then eruptions of inițial magmatites with obvious alkaline character. represented by bostonite porphyries and paleo- trachytes. The Liassic inițial magmatites appear as volcanic products in the Codlea sedimentary basin and as veins and dykes in the Făgăraș crystal- line schists (M a n i 1 i c i . 1956). In the Codlea basin. M an i 1 i c i and Vile ea nu (1963) pointed out an intercalated effusive-pyroclastic complex in the Liassic deposits. The eruptive rocks are represented by agglomerates, microagglomerates and trachytic and. keratophyric tuffs, the latest being the augite and olivine, sometimes biotite basalts. The authors consider that the erup- tions were associated with the late Kimmerian movements. At the same time there form veins and diabase dykes, serpentinizated ultramafic rocks, syenites, bostonites and camptonites that cross the crystalline schists from the Făgăraș Mountains in the general direction NE (Savu, Schuster, 1971). According to Manii ici and Vile ea nu (1963) all these eruptions would belong to a petrologie province, situa- ted in the south-eastern part of Trausylvania, in which the differentia- tion of the basaltic magma displayed towards the alkaline terms. The basic and alkaline rock veins from the crystalline schists zone at Tulgheș and in the rest of the East Carpathians might also belong to this province. C i o f 1 i c a et al. (1965) showed that, in the Perșani Mountains, the Mesozoic inițial magmatism manifests also in the Lower Cretaceous. Institutul Geological României 9 GENESIS OF THE AJLPJNE OPHIOLITES FROM ROMANIA 63 The products of this new phase of magmatic activity are represented by dolerites and basic tuffs, associated with radiolarites, that intercalate in the Neocomian deposits. In the Southern extremity of the East Carpathians, Murgeanu and Patrulius (1959) mentioned various levels of spilitic rocks intercalated in the Sinaia and Azuga beds, formations whosc age is between the Upper Jurassic and the Neocomian. The spilitic lava flows associate with red clay deposits and radiolarites. Unlike the East Carpathians where the activity of the Alpine ini- țial magmatism lasted from the Triassie to the Lower Cretaceous, mani- festing therefore in the two successive oceanic zones, in North Dobrogea, this magmatism manifested only in the Triassie intracontinental oceanic zone, which closed definitely with the old Kimmerian movements, when the obduction of the basic rocks over the East European continent takes place (Savu et al., in press7). The inițial magmatism manifested from the Upper Anisian to the Carnian as a volcanism of “withinplate” oceanic islands that gene- rated an important complex of diabase-spilitic rocks. Petrographical data on the basic rocks have been known since 1931, belonging to S a v u 1. The recent researches carried out by S a v u et al. (1980) showed that the diabase-spilitic roeks consist of basalt flows, amygdaloidal basalts and variolites that are frequently in pillow lava facies, forms whose matrix may be glassy or carbonatic. These rocks are intercalated with levels of volcanic tuffs and breccias cemented with calcite as well as levels of grey or red Triassie limestones. Small bodies or sills of gabbro- dolerites and spilitic dolerites also appear, their Na2O quantities varying between 4.77 and 5.20 %. The spilites are the result of the differentiation in the depth of the tholeiitic magma, that emiched in Na2O and volatile components. A titanaugite showing the following optica! properties is characteristic of the diabase-spilitic rocks in this region : Ng = reddish to violet-lilac, Nm = reddish, Np = reddish; c A Ng = 55°. The magmatic activity in the oceanic zone of North Dobrogea closes with veins and dykes of porphyric rocks that are distributed on two alignments (S a vu et al., 1979) 8: one situated between Isaccea and Somova, in front of the suture zone represented by the Luncavița- Consul tectonic line and another, situated behind this zone, between Văcăreni and Consul (Savu et al., in press9). 2. The Alpine Ophiolites and Initialites from the South Carpathians. The present data show that the Alpine inițial magmatism manifested in the South Carpathians only during the evolution of the Jurassic- Neocomian oceanic zone. 7 H. S a v u, U dr esc u Constanta, X ca c ș u V a s i 1 i c a (1980) Structura și geneza diabazelor din zona Luncavița-Isaccea-Minăstirea Cocoș (Dobrogea de Nord) (in press). 8 Arch. I.G.G., București (1979). 9 Quoted papers, point 7. Institutul Geologic al României 64 H. SAVU 10 The products of the Alpine inițial magmatism are extremely rare in the Getic nappe domain. Only basic tuffs that intercalate in the Oxfordian-Kimmeridgian limy deposits from the Reșița-Moldova Nouă zone are pointed out (R ă i 1 e a n u et al., 1964). The initialites of the Danubian Autochthonous from the South Carpathians are more important; here the inițial magmatites are much more varied, are found in severa! regions and occur at various levels in the Mesozoic formations. The most characteristic ophiolitic rocks are those situated in the Severin nappe in the Mehedinți plateau. In this zone, Codarcea (1940), Codarcea et al. (1961) and Năstăseanu (1976) describe an Upper Cretaceous Wildflysh formation, overlain by ophiolitic rocks that associate with formations from the Azuga beds and are overlain by the Sinaia beds, both of them being of Upper Jurassic-Neocomian age. The ophiolites consist of green rocks, serpentinites, diabases and gabbros as well as rocks making up lenticular masses and elongated bands of serpentinites and laminated diabases, that include blocks of paragneisses, micaschists, quartz amphibolites etc., making up a typical ophiolitic melange formation (Savu et al., 1978 b). As regards the genesis of this formation, the ophiolites and the associated sedimentary deposits are considered to have formed together in the Severin trough with oceanic type floor. During the formation of the Severin nappe, the ophiolites were pushed eastwards, giving rise to the melange formation of tectonic nature. Dinii trie vi 6 and Dimitrievifi (1973) also described a melange formation in the Vardar zone from Serbia. Basic and ultramafic rocks coming from an oceanic crust are known along the thrust plane of the Getic nappe over the Autochthonous in the Parîng Mountains and Retezat Mountains, where they were pointed out by G h i k a - B u d e ș t i (1932) and Paliuc (1937). In the Parîng Mountains, M a r i a Pavelescu and Pavelescu (1965) showed that the ultramafic rocks are either pre-Alpine or post-Liassic, the latter being hosted in the Upper Jurassic formations. The age of these bodies of ultramafic rocks is very difficult to establish. A volcano-sedimentary complex developa in the Arjana zone in the north-western part of the Danubian Autochthonous, extending 35 km in length (Codarcea et al., 1961). The volcanic activity took place in two phases: a Jurassic, post-Toarcian-Aalenian one and a Lower Creta- ceous one (Năstăseanu, 1976). The volcanic rocks consist of basalt flows, spilites, amygdaloidal spilites, basaltic tuffs, associated with lime- stones containing tuffogenous elements, rocks crossed by alkaline amphi- bole paleotrachyte veins. G h e r a s i (1962) 10 studied the inițial magmatites in the «urassic formations from the Țarcu Mountains, attributed even to the Carboni- ferous by some authors. They consist of diabase veins, sometimes amygda- loidal rocks, spilites and keratophyres and severa! small bodies of serpen- 10 Arch. I.G.G., București. Institutul Geological României 11 GENESIS OF THE ALPINE 'OPHIOLITES FROM ROMANLA 65 tinites. These rocks associate with a volcano-sedimentary complex formed especially of pyroclastics and spilite flows in pillow lava facies and kera- tophyres. The whole series constitutes a spilite-keratophyric association as meant by D e w e y and F1 e 11 (1911). We mention that the presence of some spilite bodies in the base of the Cenomanian-Turonian Wildflysch was pointed out in the northern part of Oltenia by M u t i h a c (1964) and on the Cerna Valley in Banat by Xăstăseanu (1968). Their significance was discussed by Savu (1968). At present the question arises -whether they are in situ flows or represent olistolites or olistostromes of Jurassic or Lower Cretaceous magmatites included in the Wildflysch. 3. The Ophiolites and Other Initialites from the Mureș Zone in the South Apuseni. The Mureș zone comprises the most interesting ophiolitic complex in Romania. Unlike the Carpathian chain zone, the ophiolitic rocks in this zone were very little affected by the plicative tectonic move- ments that manifested more intensely on the margins of the oceanic zone, owing to the limited bilateral subduction (Savu, 1976) or collision processes that led to the formation of overthrusts and folds facing the sialic plates to the NNW and SSE (see the annexed map). Wider folded structures, comprising the eruptive rocks, the jaspers and flysch formations are found also in the median part of the zone with ophiolitic rocks (Savu, N ic ola e, 1975). For this reason, the Mureș zone, which extends on 200 km, appears as a bilateral orogen (M a c o v e i, A t a n a s i u , 1934), under which the Moho surface lies at the depth of 33 km. It functioned as an oceanic zone, partly oceanized, whose floor was formed of simatic rocks and also of some sialic elements (Savu, 1976) consisting of crystalline schists and Permian sandstones which appear as blocks in polygenous agglomerates of Upper Jurassic island arc basalts developed in the eastern part of the zone, from the Vorța meri- dian eastwards (Savu et al., in press11). The pre-orogen inițial magmatism that lasted 60 m.y., comprised three evolution stages : 1) the first stage begins in the Lower Jurassic when the first basalt eruptions start (180 m.y.) and lasts to the Oxfordian, when the bilateral underthrusting process begins and the newr Kimmer- ian movements respectively; 2) the second stage begins in the Oxfor- dian and lasts to the Neocomian (140 m.y.), its magmatites being asso- ciated with the first sedimentary deposits; 3) the third stage is in the Apțian-Albian (120 m.y.), being followed by the Austrian movements with which the oceanic zone closes completely. Ocean floor ophiolitic rocks formed in the first stage coinciding with the spreading phase of the oceanic zone, while island arc calc- 11 Savu H., Udrescu Constanța, Neacșu Vasilica (1980). Consi- derații asupra petrologie! și metalogenezei inițialitelor alpine din regiunea Vălișoara-Dumești (Munții Metaliferi), cu observații asupra fundamentului prealpin (in press). S - C; 658 1 Institutul Geologic al României Vigrz 66 H. SAVU 12 alkaline and alkaline inițial magmatites erupted in the following two stages (Savu et al., 1978 a). The ophiolitic rocks in the first stage make up an important com- plex, over 3000 m in thickness, developing in the axial part of the Mureș zone, from Almaș-Seliște to Pătîrș, where the zone is covered by Neogene sedimentary deposits (Savu, 1976). Ophiolitic rocks also occur in some places of the eastern part of mobile zone, in the Bunești region, where they come out of the basement from under the volcanics belonging to the second stage (Savu et al., 1978a). The ophiolitic rocks are represented by submarine flows of ophitic basalts, anamesites that are frequently in pillow lava facies. These lavas are very seldom associated with basic pyroclastics, represented sometimes by tachylyte or palagonite glasses. The magmas from which they resulted formed in the upper mantie, as shown bv the value of the Sr87/Sr80 ratio, situated between 0.7021 and 0.7056 (H e r z et al., 1974). Except some small jasper intercalations between the basalt flows from Dumbrăvița, the sedimentary deposits are altogether absent. On the Southern border of the oceanic zone, where the erosion was more intense, the basalts contact the pre-Alpine crystalline schists of the sialic plates (Savu, 1976). Intercalations of recrystallized limestones situated on the Căpîlnaș-Zam-Vorța-Furcșoara alignment appear in the upper part of the basaltic complex only during the Oxfordian, at the end of the magmatic activity from this stage. These limestones are supposed to have formed on the Southern margin of the geosyncline in the shelf zone (Savu, Nicolae, 1975). During the formation of the basalt complex some magma intrusions took place; several gabbro bodies of small size (3 — 5 km long) and bodies of ultramafic rocks (300 — 400 m long) formed of them. At the contact of the gabbro bodies there are basic hornfelses with pyroxenes, formed at the expense of the basalts in which they were intruded. They belong to two main categories : 1) simple bodies, formed of a single intrusion of basic magma and 2) composite bodies, resulted from several intrusions. The gabbro bodies belonging to the first category, like those from Căzănești-Ciungani (Fig. 2 a) and Almaș-Seliște (Fig. 2 d), show a layered structure, formed by the differentiation in situ of the magma intruded in the basalt complex. They present a horizon of dole- rites and microgabbros in the lower part, overlain by a horizon of gabbros with vanadium titanomagnetite, which may have a rhythmical layered structure (Almaș-Seliște); this horizon in its turn underlies a thicker upper horizon consisting of diopside gabbros or quartz gabbros (Giușcă et al., 1963). This latter horizon is overlain by another horizon at Almaș- Seliște, consisting of gabbro-anorthosites and anorthosites (C i o f 1 i c a, Savu, 1963). The iron concentration in the lower horizon of magnetite gabbros formed due to the gravitațional differentiation of the tholeiitic magma, a process depicted on the diagram from Figure 3. It took place towards Institutul Geologic al României XJGR/ 13 GENESIS OF THE ALPINE OPHIOLITES FROM ROMANIA 67 the end of the liquid-magmatic stage, being favoured by the Fe2O3 pre- sence in the residual magma and the variation of the pressure of the volatile components within the gabbro bodies during their consolidation (C i o f 1 i c a , Savu, 1962 ; 1963). The composite gabbro bodies, like those from Almășel, Cuiaș (Fig. 2 c), j ulița, Baia and Dumbrăvița are formed of a more important intrusion, consisting of diopside gabbros, showing an incipient gravita- l-’ig. 2. — Geological section through the gabbroic and ultramafic bodies from the Mureș zone (according to Ci of li ca and Savu, 1962). a, stratified gabbro intrusion from Căzănești-Ciungani; b, ultramafic rock body from Roșia Nouă ; c, composite gabbro body from Cuiaș ; d, body with rhythmical stratification from Almaș Scliștc, 1, basalts; 2, gabbros; 3, olivine gabbros; 4, dolerites; 5, melagabbros; 6, magnetite gabbros: 7, peridotites : 8, microgabbros; 9, magncliLe dolerites, hyperites and gabbros; 10, gabbroanorthosltcs and anorthosites; 11, quartz gabbro; 12, Laramian intrusions. tional differentiation and a succession of small intrusions of olivine gab- bros, hyperites, quartz diorites and granophyres. In the western part of the Mureș zone, between Dumbrăvița, Baia and Lupești, there developa an important complex of sheeted dykes and small bodies of dolerites and gabbros, sometimes granophyres, that differentiated at depth and then were intruded into the basalt complex. The bodies of ultramafic rocks from Roșia Nouă (Fig. 2 b), Corbești and Almaș-Seliște also show a layered structure, with a horizon of perido- tites partly serpentinizated in the base, followed by a layered horizon with melagabbros and troctolites, covered by an upper horizon of olivine gabbros (Savu, 1962 a; Savu et al., 1970). Towards the end of this stage the spreading of the oceanic zone seems to undergo a change, and the first rocks bearing free quartz, such as quartz diorites and granophyres, occur in the oceanic zone. Institutul Geological României 68 H. SAVU 14 During the second iniția,! magmatic stage, the subduction or colli- sion process 12 of the two sialic plates under the ophiolitie zone begins concomitantly with the new Kimmerian movements. Thus we witness the transformation of the oceanic zone into a zone with two island ares, situated on the margin of the two plates that sink under the mobile zone. 13 The rising of the axial ophiolitie zone and respectively the sinking Fig. 3. - FeO + F^O, - MgO - —Na2O + K2O diagram for the differentiation of the tholeiitic magma in the gabbro bodies from Almășel and Căzănești-Ciungani. 1, Almășel gabbros ; 2, Căzănești- Ciungani gabbros ; a, gabbros ; b, olivine gabbros; c, magnetite gabbros ; d, granophyres ; e, anor- thosites. of the geosyncline margins take place, forming two marginal troughs in which the sedimentation of the flysch with red argillites and jaspers begins and a pre-orogen volcanism, characteristic of the island ares (Savu, in press)14 or a submarine island arc volcanism manifests (M i t c h e 11 and Bell, 1973). 12 The bilateral subduction (underthrusting) process is obviously one hypothesis. Ano- ther hypothesis would be the collision of continent/continent type of the Apuseni Mountains microplate (AMMp) and the Transylvanian microplate (TMp) on Figure 1, underneath the ophiolitie complex, during the new Kimmerian movements, determining the bilateral obduc- tion of the ophiolitie rocks. Whatever process manifested, it brought about a change in the structure of the oceanic zone and generated the calc-alkaline and alkaline volcanism in the island ares of Upper Jurassic-Lower Cretaceous age from the Mureș zone. 13 Taking into account the Austrian movements, which are considered to be the first main orogenesis of the Alpine cycle, since the inițial magmatism closes before it, the island are volcanism from the Mureș zone should be considered as pre-orogen. But from a genetic point of view, it is generated by the new Kimmerian movements (Oxfordian-Kimmeridgian) which, although weaker in comparison with the Austrian ones, determine a change in the evolution of the Alpine inițial magmatism, conditioning the passage from the ophiolitie ocean floor magmatism to an island arc volcanism showing a calc-alkaline and alkaline character. The latter presents severa! peculiarities in comparison with the present island arc volcanism. 11 Quoted papers, point 3. 15 GENESIS OF THE A1.PINE OPHIOLITES FROM ROMANIA G9 The melting of the sialic material at depth takes place in large amounts. The acid magma mixes up with and contaminates the basic one, determining the formation of various rocks showing a calc-alkaline or alkaiine character, such as basalts, basaltic andesites, limburgites and picrites, coming from the basic magma, various types of andesites, oligo- phyres and orthophyres coming from hybrid magmas (Sr87/Sr86 = 0.7043 — 0.7073) and dacites associated with rhyolites formed of the acid magma of sialic origin. This volcanic activity manifests in the western part of the zone, especially, in the two marginal troughs, along the two volcanic arcs, but it covers the whole surface of the oceanic zone in the eastern part, where the ophiolites from the first stage are less developed. The eruptions take place under submarine conditions, show an ex- plosive and recurrent character and develop especially round some volcanic centres, giving rise especially to pyroclastics (Savu, 1962 b, 1962 c). The volcanic materials associate with reef limestones and intercalate in Upper Jurassic-Lower Cretaceous flysch deposits represented by jaspers, red argillites, limestones and marly limestones rich in volcanic material. In the third evolution stage the inițial magmatism manifests only by spilite flows, intercalated in the Apțian-Albian flysch deposits from the eastern part of the Mureș zone. The Sr87/Sr86 ratio, which is of 0.7041 also indicates a simatic origin of some of these spilitic magmas. The Metamorphism of the Ophiolitie Rocks The ophiolitie rocks as well as the other associated inițial magma- tites were not affected by regional metamorphism processes, but only by a hydrothermal metamorphism or autometamorphism. These processes were determined either by the inițial magmatism activity, as in most regions, or by the latter activity and the Tertiary eruptions, as in the Mureș zone. Except some small differences, the effects are similar and, according to the parageneses forming in the basic rocks, they can be compared with the conditions of the regional metamorphic facies (S a v u, 1967). The highest temperature Solutions that acted at great depth, determined uralitization phenomena of the pyroxene, entailing actinolite and epidote (pistacite) formation as well as saussuritization phenomena of the plagioclase. These transformations that occurred at 400 — 500°C would belong to the epidote-amphibolitic facies. It is also now that the serpentinization of peridotites and the metamorphism of limestones from the upper part of the ophiolitie complex take place. Albite-sericite-chloritc-calcite(-prehnite) rocks form at a lower tem- perature and atasmaller depth, usually with remnants of minerals from the primary mineralogical association, as in the above case. This parage- nesis would correspond to the green schist facies. Metamorphism processes belonging to the zeolitic facies are noticed in the Mureș zone, and more rarely in other zones. They are determined by the lowermost temperature Solutions and manifest by zeolite deposi- 4 ' L In s ti tutui Geological României \ IGR/ 70 H. SAVU 16 tion on the fissures and in the rock vacuoles or by the feldspar zeoliti- zation in the rock composition. Petrology and Geoehemistry The ophiolitic rocks and the inițial magmatites from Romania, formed in the oceanic zones from the northern part of the Tethyan Sea, show a quite varied composition as compared to the rocks formed in Fig. 4. — QLM diagram for the rocks from the Mureș zone. 1, ophiolitic rocks; 2, is- land arc volcanic rocks as- sociated with the ophioli- tes ; a, ophiolitic rocks field; b, island arc volca- nics field. the same period in the principal oceanic zone of this sea, which extended from the Alps through Turkey to the Himalaya. As in some Carpathian oceanic zones the ophiolitic rocks intimately associate with the other initialites, such as the basic rocks of the island arc volcanism, their separation can be made only by detailed researches, taking into account the rock occurrence, the way of manifestation of the magmatism, the rock structure, the mineralogica! and Chemical composi- tions and especially the distribution of the inert trace elements. The comparison of the Chemical composition of the inițial rocks from the Mureș zone with that of the ophiolites from the Alps, the Apen- nines and the Dinarides studied by B u r r i and N i g g 1 i (1945), shows that the magmatites from the first stage of the inițial magmatism, that is the pre-oxfordian stage, represent typical ophiolites (Savu, 1962 d). The basaltic and gabbroic rocks are projected on the diagram on Figure 4, in the field of the basic ophiolites from the three mentioned classical regions. The peridotites and the rocks close to them in the Mureș zone shift towards the corner M of the diagram, towards the field of the ultramafic ophiolites from the three regions. Institutul Geological României 17 GENESIS OF THE ALPINE OPHIOLITES FROM ROMANIA 71 The diabase-spilites from North Dobrogea (Savu et ah, 1980) and obviously other ophiolitic rocks from the Carpathians also lie in the field of basic ophiolites. The island arc volcanics differ from the ophiolites. These rocks show a calc-alkaline character, such as those from the second and third stages in the Mureș zone, that formed under special subduction condi- Fig. 5. — Ti—Y —Zr dia- gram for the rocks from the Mureș zone. 1, ophiolitic rocks, 2, is- land arc volcanic rocks as- sociated with the ophio- lites. Ti/100 tions and contamination of the basaltic magma. These rocks move away from the field of the ophiolitic rocks, towards corner Q of the diagram (Fig. 4), indicating a gradual SiO2 enrichment of magmas. They resemble the porphyries from Dobrogea, the andesitip, alkaline and acid rocks from the Perșani Mountains-Codlea-Făgăraș Mountains region and the acid and alkaline rocks from the spilite-keratophyre series from the Arjana zone of the Danubian Autochthonous. The ophiolitic rocks formed in the first evolution stage of the inițial magmatism in the Mureș zone show similar geochemical characteristics to those of the ocean floor basalts (Savu et al., 1978 a) as results from Figure 5, drawn according to P e a r c e and C a n n (1973). The origin magma formed in the upper mantie and erupted in the ocean spreading stage, forming a ridge in its axial zone, that developed up to the Oxfor- dian, when the evolution sense changes, tending to close and ending with the Austrian movements. The ultramafic rocks and some spilites from the East Carpathians belong to the same category (Săndulescu- Busso et al., in press15), while the serpen tinites and diabases of the “melange” formation from the Severin nappe should be also attributed to this category. 15 Quoted papers, point 6. H. SAVU 18 Some differences are noticed in the diabase-spilites from North Dobrogea, which are distributed in the field of the basalts from the “withinplate” oceanic islands (Fig. 6), such as those from Hawaii (Savu et al., 1980). Similar features are shown also by some spilitic rocks from the Wildflysch klippes of the East Carpathians 16. H <5 c k (1976) describes a similar situation in the Eastern Alps. Fig. 6. — Ti—Y—Zr dia- gramforthe Triassic dia- base-spilitcs from North Dobrogea The inițial magmatites from the second and third stages from the Mureș zone obviously belong to the field of the volcanics from the island arcs, as shown by Savu et al. (1978 a). The same peculiarities are to be found also in some rocks from the klippes of the East Carpathians as well as in other similar magmatites from the Carpathian chains. We note that the alloehthonous rocks from the Barău-Hăghimaș syncline resulted from the two oceanic zones, the Triassic one and the jurassic-Neocomian one, where ocean floor basalts and spilites, “within- plate” oceanic island basalts and spilites, like those from North Dobrogea as well as island arc volcanics were found. Mctallogenesis The useful mineral substances associated with the ophiolitic rocks and the Alpine initialites are represented by low vanadium titanomagne- tite concentrations in gabbros (Fig. 2) and sulfides with the pyrite- chalcopyrite (-hematite) paragenesis in stockwork type structures from the South Apuseni (Savu, 1972). 16Săndulescu-Russo et al., quoted papcrs, point 6. Institutul Geological României 19 GENESIS OF THE ALPINE OPHIOLITES FROM ROMANIA 73 Chalcopyrite, pyrite and magnetite hydrothermal mineralizations formed in connection with the Almășel gabbro body. Cyprus type strati- form copper mineralizations formed in the South Carpathians at Baia de Aramă. The calc-alkaline and alkaline magmatites from the pre-orogen island arc from the Mureș zone (the Apuseni Mountains) are associated with manganese oxides in the red argillites and radiolarites from the Pîrnești-Șoimuș-Buceava district and the Pb, Zn and Cu mineralizations from the Vorța region, while the Upper Triassic quartz porphyries (rhyoli- tes) from North Dobrogea, situated in front of the ophiolitic suture, are connected with barite concentrations with which Cu, Pb and Zn sulfides associate. Conclusions The following main conclusions arise from this paper. The ophiolites and the other initialites from Romania are found in various States : 1) in autochthonous position, like those in the Mureș zone, where some overthrusts appear only in the marginal parts, the other ophiolites being affected only by folding processes; 2) in overthrust nap- pes, as in the East Carpathians and especially in the South Carpathians, where the melange formation is also found; 3) in klippes included in Wildflysch as in the East Carpathians ; 4) obducted, as in North Dobrogea. Unlike the classic Alps-Himalaya oceanic zone, the inițial pre-orogen magmatism from the narrow oceanic zones, formed between the micro- plates from the northern part of the Tethyan Sea, provided especially effusive rocks and, to a lower degree, intrusive rocks. The layered structures of the small bodies of gabbroic and ultra- mafic rocks, as well as the contact metamorphism determined by some of these bodies on the basaltic complex in which they are hosted, are peremp- tory arguments that these bodies do not represent fragmentă removed from the upper mantie and tectonically thrown or pushed in the basaltic complex, as some geologists would think, but they are intrusions of tholei- itic magma coming from the mantie, that differentiated “in situ”. The classic layered structures of the complexes of ophiolitic rocks from Greece and Cyprus was not pointed out in any of the Carpathian zones, which indicates that the three members of an ophiolitic sequence (peridotite-gabbro-basalt) may be found not only in superposition but also in intrusion relations (Mureș zone). The oceanic zones in the north of the Tethyan Sea differ from the classic zones by the low amount of ultramafic rocks and the presence of the volcanics formed in zones of pre-orogen (submarine) island arcs, that lack in the classic zones. In the Mureș zone we even witness the transition from the stage of a zone with ocean floor ophiolites to the stage of an island arc volcanic zone. Institutul Geological României IGR 74 H. SAVU 20 The magmatic activity took place in oceanic zones with simatic floor, as in the Severin trough and a part of the East Carpathians, or with partly simatic and partly sialic floor, as in the Mureș zone. Most of the ophiolitie rocks show characters of ocean floor basalts ; only the diabase-spilites from North Dobrogea and some of the klippes from the East Carpathians, probably of the same age, are “withinplate” oceanic island magmatites. The other initialites, which are present in small amounts, associate with the ophiolites in all the Carpathian zones ; they are island arc volcanics, show characters of calc-alkaline and alka- line rocks and form in the same time interval of the Alpine oceanic zones, in which, only ophiolitie rocks form in the classic zones. The general conelusion is that in the oceanic zones from the Tethyan Sea, the ophiolites — ocean floor or ocean plate formations — show various situations depending on the structure and the particular evolution conditions of those zones; in other words, there are ophiolites and ophiolites as there are “granites and granites”. REFERENCES Auhoin J. (1965) Geosylclines, Elsevier Press, p. 1—335, Amsterdam. B 1 e a h u M. (1974) Zone de subducție în Carpații românești. D.S. Inst. geol., LX/5 (1972 — 1973), 5—25, București. Brongniart A. (1813) Essai d’une classification mineralogique des roches melangâes. Jour. Mines, XXXIV, Paris. Bruno J. H. 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Geol., Geophys., Geogr., Giol., 20, 1, 67 — 75, București. — Vasiliu Cecilia, Udrescu Constanța (1970) Geochimia și petrologia ofiolitelor din prima etapă a evoluției magmatismului inițial alpin din masivul Droeea (Munții Apuseni). D.S. Inst. geol., LVI/1, 219—252, București. — S c h u s t e r A. C. (1971) Structura și petrologia șisturilor cristaline din regiunea Șinca Nouă-Holbav (Munții Făgăraș). D.S. Inst. geol., LVII/1, 89 — 114, București. — Udrescu Consta nța (1973) Geotectonic Evolution of the Mureș Zone and the Distribution of Trace Eleinets in Its Ophiolitie Rocks. International Symposium on Vol- canism and Associated Metallogenesis, Bucharest, Abstracts, 182 — 183. — N i c o 1 a e I. (1975) Evolution of Ophiolitie Vulcanism in the Vorța Region and Its Position in the Mureș Zone Tectogenesis (Apuseni Mountains). D.S. Inst. geol. geofiz., XLI//5, 179-196, București. — M a ier O., V a s i 1 i c a N e a c ș u, U d r e s c u C o n s t a n ț a (1977) Petrografia și geneza corpului de roci ultrabazice de la Cuca-Munții Semenic. D.S. Inst. geol., geofiz., LXIII/1, 113-130, București. — Berbeleac I., Călin eseu Erna, FI or eseu Rodie a, Ză m i r că Al la (1978a) Structure and Origin of Bunești Gabbroic Body (Metaliferi Mountains). D.S. Inst. geol geofiz., LXIV/1, 173—191, București. Institutul Geological României GENESIS OF THE ALPINE OPHIOLITES FROM ROMANIA 23 77 — Năstăseanu S., Lupu M., Nic ol a e I. (1978b) Ophiolites and Sedimentary Formations in South Apuseni and Southern Carpathians. Guidebook for the Field Works of the 2.1. and 2.2. Groups, Publ. I.G.G., 1 — 43, Bucharest. — Constanța U drese u, Vasilica N ea c ș u (1980) Structural, Petrologie, Geochimic and Genetic Study of the Ophiolites in Niculițel Zone (North Dobrogea). D.S. Inst. geol., geofiz., LXV/1, București. S a vu 1 M. (1931) Erupțiunile de diabaze din nordul Dobrogei D.S. Inst. Geol. Bom., XVIII, 231—255, București. Săndulescu M. (1976a) Contribuții la cunoașterea stratigrafiei și a poziției tectonice a seriilor mezozoice din bazinul superior al Văii Moldovei. D.S. Inst. geol. geofiz., LXII/5, 149 — 176, București. (1976b) Essai de synthese structurale des Carpathes. B.S.G.F., (7), XVII, 299 — 358, Paris. Steinmann G. (1927) Die Ophiolitischen Zonen in den mediterranen Kettengebirgen. C.R. 14 Congr. Geol. Intern. (1926), Madrid. St iile H. (1940) Einfiihrung in den Bau Amerikas. Berlin. Institutul Geological României Institutul Geological României H.SAVU - Geneiis of the Alpine Ophiolites from Romonio Imprim. Atei Inst Geol Geor. Institutul Geological României ANUARUL INSTITUTULUI DE GEOLOGIE $1 GEOFIZICA. VOL. LVI Projecl 39: Ophiolites of Continents and Comparable Oceanic Rocks ALPINE OPHIOLITES OF ROMANIA : TECTONIC SETTING, MAGMATISM AND METALLOGENESIS1 BY GRAȚIAN CIOFLICA3, MARCEL LUPU3, IONEL NICOLAE3, ȘERBAN VLAD3 Ophiolites. Alpine tectonics. Magmatism and mctallogenesis. Tholeiitic magma. Ocean floor expansion. Subduction; Romania. Sommaire Ophiolites alpines de R o u manie: cadre tectonique, mag- ma t i s m e e t m 61 a 11 o g e n 6 s e. L’essai de syst6matiser les ophiolites alpines de Rou- manie par rapport aux cadres tectoniques encaissants a mis en Evidence les suivantes parti- cularites : — Les ophiolites li6es â la riftogenfcse avort^e occurrent dans le bassin ensialique de dâbut des Monts Apuseni du Nord et dans l’aulacogene de la Dobrogea du Nord ; la mătallo- genăse est limitee aux modiques sAgrigations magmatiques de Fe—Ti de ia Dobrogea du Nord. — Les ophiolites liees aux zones d’expansion se trouvent dans le soubassement de la Depression de Transylvanie, dans les nappes de Hăghimaș-Rarău et Persani et dans les nappes du Flysch noir, Ceahlău et Severin confin6es â la periphârie d’un paleobassin des Carpathes externes. La mătallogenese est assignee aux occurrences de type Cypr; locilisfees dans la nappe de Severin. — Les ophiolites li6es a ix zones de sibductiou sont renrăsentfces par les associations d’arc insulaire et de bassin mar -inal actifs des Monts Apuseni du Sud et la mătallogenăse as- soci6e pai- les segrăgations magmatiques de Fe —Ti —V, les mineralisations de Cu ou de Zn — — Pb —Cu attribuees probablement aux typcs Cypre et respectivement Kuroko, ainsi que les mineralisations volcano-sedimentaires de Mn. 1 Paper received on April 7, 1980 and accepted for publication on April 17, 1980. 2 Facultatea de geologie și geografie. București. 3 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. Institutul Geological României GR. CIOFLICA et al. 80 2 The significance of the ophiolites was differently interpreted by various geologists. It is however likely that ophiolites represent the consanguineous association of basic and ultrabasic rocks and their diffe- rentiation products with autochthonous and/or allochthonous position related to various tectonic settings (that is ocean-floor spreading zones, but also short-lived rifts, immature island arcs, active marginal basins and ocean islands). The present paper attempts to review the occurrences of the Alpine ophiolites of Romania in connection with the different tecto- nic settings which controlled their formation and emplacement. I. Ophiolite Oceurrcnces The Alpine ophiolites of Romania occur in the Carpathians and in the North Dobrogea orogenic System (Fig. 1). The Carpathian ophiolites are found in the East Carpathians, the South Carpathians and the Apuseni Mountains in association with sedi- mentary formations of Upper Permian-Lower Cretaceous age. The East Carpathian ophiolites are related to the following units : a) the Hăghimaș- Rarău and Perșani Nappes that belong to the Transylvanian Nappe System of Middle Cretaceous deformation; b) the Black Flysch and Ceahlău Nappes that belong to the Upper Flysch Nappes of Late Cretaceous defor- mation. The South Carpathian ophiolites are related to the Getic and Severin Nappes and the Danubian Autochthon that underwent Middle and especially Upper Cretaceous deformations. In the North Apuseni Moun- tains the ophiolites are associated with rhyolites and Permian sedimentary rocks of the Moma and Dieva Nappes, which resulted during Pre-Gosau deformations. Finally the South Apuseni Mountains area is characterized by widespread Jurassic-Lower Cretaceous ophiolites in connection with various tectonic units involved in Middle and especially Late Cretaceous deformations. Beyond the Carpathian region, Middle Triassic ophiolites are found in intimate connection with rhyolites and sedimentary rocks of the Tulcea Zone that belong to the North Dobrogea orogenic System involved lately in Kimmerian deformations. II. Ophiolite Systems The Alpine ophiolitic magmatism was controlled by various geolo- gical and tectonic settings which exhibit different stages of evolution. Thus, the unevoluated tectonic setting represented by short-lived rift Systems yielded a bimodal (ophiolitic and rhyolitic) magmatism (Fig. 2). All the more, the evoluated tectonic setting (Fig. 3) gave rise to ophioli- tes in close connection with ocean floor spreading zones (tholeiites and alkaline differentiation products) or subduction zones (tholeiite to calc- alkaline products and final alkaline trending products) of islandic arc type and spilites of active marginal basin type; taking into account Institutul Geological României 3 ALPINE OPHIOLITES OF ROMANIA 81 Institutul Geological României 82 GR. CIOFLICA et al. 4 their formation and tectonic emplacement, the subduction related ophio- lites are actually much wider developed than the ocean floor spreading related ophiolites. A—x----------B x----c \///M [^^2 E3$ 1^1» l ^ls EEEh F—> |»»:|8 ElE# Fig. 2. — Cross-section through the Tulcea Zone aulacogen (geological data according to Patrulius et al., 1974, unpublished data). 1, Hercynian folded area ; 2, Lower Triassic; 3, Middle Triassic ; 4, Triassic rhyolites; 5, Triassic ophiolites; 6, Upper Triassic; 7, Lower Jurassic; 8, Lower-Upper Jurassic; 9, Cretaceous ; 10, Tertiary; A, Măcin Zone : B, Tulcea Zone; C, Pre-Dobrogean Depression. ACTIV ISLAKO ȚRANSVLVANIAN MARGINAL ARC RIFT Fig. 3. — Hypothetical cross-section through the South Apuseni Mountains during Barretnian times. 1, continental crust type ; 2, oceanic crust type; 3, Feneș Beds associated with the spilitic complex; 4, island arc ophiolites (tholeiitic- prevailing complex and calc-alkalic-prevailing complex); 5, Stramberg limestones ; 6, ocean- floor spreading zone; 7, inactive subduction zone. A. Ophiolites lielated to Unevoluated Tectonic Settings The unevoluated tectonic setting is represented by different deve- lopment stages of short-lived rifting system, that is definitely the Post- Hercynian-Permian incipient ensialic basin of the Codru-Moma Mountains (North Apuseni Mountains) and the Triassic-Lower Jurassic aulacogen of the Tulcea Zone (North Dobrogea). Both settings are characterized by the following features : — epicontinental sedimentation consisting of red detrial rocks in the Codru-Moma Mountains and mainly rocks of carbonate platform type in the Tulcea Zone; — bimodal magmatism that is ophiolitie (basaltic or spilitic) and rhyolitic association; — syn-diagenetic and/or epigenetic ore deposition. It is noteworthy that ophiolites lack commonly metallogenetic importance and epigenetic occurrences are confined to rhyolites. Institutul Geological României 5 ALPINE OPHIOLITES OF ROMANIA 83 In the Codru-Moma Mountains the ophiolites are found in the Moma and Dieva Nappes. These units belong to the North Apusenides orogen resulted prevailingly during Pre-Gosau deformations (I a n o v i c i et al., 1976). The most significant occurrences of Permian detrital rocks, bimodal magmatism and metallogenesis are connected with the Moma Nappe. The rifting was restricted to the graben stage, when mantie upwelling gave rise to a crusta! graben filled with red detrital sediments; the basalt-rhyolite volcanicity is characteristic of incipient ensialic basins and the metallogenesis is commonly of cupriferous type (V1 a d et al., 1980, unpublished data4). The detrital Permian rocks consist of basal “laminated conglome- rate formation”, followed by “vermicular sandstone formation” and upper coarse to fine-grained elastic sediments that contain in places acidic and basic volcanics (I a n o v i c i et al., 1976). The Permian ophiolites exhibit a well-marked spilitic character, with various (hyalo-ophitic, inter- granular, even subophitic) textures; small spilitic dolerite bodies are sporadically found, too. Rhyolite-spilite interbeddings are noticed in places. The ore deposition is prevailingly cupriferous: Cu stockworks occur within rhyolites at Rănușa and strata-bound Cu infiltration type ores are located in Upper Permian eonglomerates and sandstones at Zimbru; Ba vein mineralization is confined to the contact between ophiolites and detrital sediments at Rănușa (V1 a d et al., 1980, unpublis- hed data5). The restricted evolution of the Permian basin was marked by the accomplishment of the magmatic activity at the end of the Permian times. Hence, the significant Alpine evolution of geosyncline type that started during the Early Triassic with carbonate platform sedimentation cannot be inferred from a possible long-lived evolution of the Permian incipient ensialic basin. The North Dobrogea orogenic System resulted during Paleozoic and Kimmerian deformation events. It is bordered by two major Hercynian structures, that is the Scythian Platform in north and the Moesian Platform and contains the Macin Zone and the Tulcea Zone. The evolu- tion of the Tulcea Zone corresponds to the genetic model of an aulacogen (V1 a d, 1978), comprising the graben-downwarping stages during Trias- sic times, and the compressional-post geosynclinal stages during Jurassic and probably Early Cretaceous times. The Tulcea Zone proceeded on to Crimeea and the Great Caucasus (M u r g o c i, 1914) connecting the north of the Moesian Platform and the Pontian Massif with the Tethys. Reactivization of WNW—ESE Hercynian fractures during the graben stages controlled the development of a shallow marine environ- ment wherein mainly carbonatic sedimentation, bimodal basaltic-rhyoli- tic magmatism and Fe infiltration skarn and Alpine type Zn-Pb-barite ore deposition did occur (V1 a d , 1978). The sedimentation shows simila- rities toward European Alpine facies with certain fauna influences of the Indo-Pacific Province; eonglomerates, sandstones, clays followed by n 5 Arch. I.G.G., Bucharest. '"•A Institutul Geologic al României IGR/ 84 GR. CIOFLICA et al. 6 calc-schists occurred during Early Triassie, whereas bioclastic limestones dolostones, mioritic limestones, marly limestones and calcarenites charac- terized the Middle Triassie carbonate platform sedimentation; the Upper Triassie contains limestones and sandstones (Patrulius et al., 1974, unpublished data6). The mainly carbonatic sedimentation is accompanied by ophiolitic and rhyolitic magmatism and metallogenesis that acted commonly during Ladinian times. The ophiolites represented by spilites, basalt flows, dolerites and sporadic gabbroic bodies developed along WNW-ESE and NW—SE lineations and show mutual age relations with the rhyolites. The Alpine type Pb-Zn-barite mineralization (V Iad, 1978) is found along a WNW—ESE alignment that only partly coincides with the northern ophiolitic and rhyolitic lineation : syn-diagenetic mine- ralization produced barite strata-bound deposits lithologically controlled by Ladinian limestones (Cortelu, Bechir, Dealul Carierii), whereas epige- netic mineralization gave rise to tectonically controlled galena -psphalerite ±barite, fluorite deposits as veins in limestones (e.g. Trifan, Dobrișani, Bechir, Malcoci, Bogza) and stockworks in rhyolites (Cortelu). Concur- rent hematite skarn ores of infiltration type are controlled by the Lunca- vița-Consul line and restricted titanomagnetite segregations are connected with the ophiolites. The compressional stage took place during Jurassic and probably Early Cretaceous times; Kimmerian deformations yielded high-angle overthrusting from SW toward NE and mild folding of the Triassie cover as synchnes and anticlines. The marine deposition history of the Tulcea Zone is achieved by Jurassic detrital sedimentation filling the synclines; transcurrent movements might separate at that time the Tulcea Zone from a presumed northern part of the aulacogen. Short-lived rifting related ophiolites from the Codru-Moma Moun- tains and Tulcea Zone -were geochemically investigated. The resulting data7 were plotted in P e a r c e and C a n n (1973) and P ear c e and Gale (1976) diagrams and promoted apparent contradictions that are discussed below. Thus, using the Zr/Y — Ti/Y diagram (Fig. 4) the plots are found in the margin-plate basalts field. Major plots in the Ti-Zr diagram (Fig. 5) arelocatedbeyond thefield established by P ear ce and C a n n (1973); this anomaly is given by higher Zr values of both the Codru-Moma Mountains and the Tulcea Zone ophiolites and somehow higher Ti values of the Tulcea Zone ophiolites. The high Zr contents that commonly range between 200 and 600 ppm suggest a significant sialic contamination; ophiolites of the Codru-Moma Mountains show increased sialic contamination that is thicker sialic crust, but restricted evolution (X Zr = 360 ppm) as compared with those of the Tulcea Zone (X Zr = 245 ppm). Major plots of the Codru-Moma Mountains ophiolites are related to the low-potassium tholeiites field assigned to 6 Arch. I.G.G., Bucharest. 7 According to S a v u et al. (1980, in press) for the Tulcea Zone and Stan et al. <1980, in press) for the Codru-Moma Mountains. '.A Institutul Geological României IGR/ 7 ALPINE OPHIOLITES OF ROMANIA 85 island arcs and major plots of the Tulcea Zone to the ocean island basalts and continental basalts fields of the Ti/100 — Zr — 3Y diagram (Fig. 6). Analyses of the Codru-Moma Mountains ophiolites show rather constant Ti values with respect to ocean-floor basalts and increased Zr values due to sialic contamination; thus, the plots chister in the field C closer to the Zr corner. On the other hand, analyses of the Tulcea Fig. 4. — Zr/Y — Ti/Y diagram. 1, Codru-Moma ophiolites ; 2, Tulcea Zone ophiolites; MPB, îield of the plate margin basalts ; WPB, field of the within plate basalts. Zone ophiolites that exhibit higher Zr and Ti contents than those of the ocean-floor basalts are plotted in the field D, suggesting rather the sialic influence than the affiliation to within-plate basalts (see Fig. 4). The Ti-Cr diagram (Fig. 7) indicates a homogeneous distribution of the plots on both of the low-potassium tholeiites (LKT)-ocean-floor basalts (OFB) line for the Codru-Moma Mountains ophiolites, whereas the Tulcea Zone ophiolities exhibit affinities toward the ocean-floor basalts field; accordingly it seems likely that the Codru-Moma Mountains ophiolites occurred in connection with a less evoluated riftingas compared with the North Dobrogea rifting, confirming similar above-mentioned statements. Thus, the apparent contradiction provided by short-lived rift ophio- lite analyses are, however, to be explained by the differentiate evolution and the various sialic thickness that altered the characteristics of the primary magmas. Institutul Geological României 86 GR. CIOFLICA et al. hoo'oz Fig. 5. — Ti-Zr diagram. Codru-Moma ophiolites ; 2, Tulcea Zone ophiolites; field A, low-potassium tholeiite; field B, ocean-floor basalts, low-potassium tholeiites or calc-alkalic basalts; field C, calc-alkalic basalts; field D, ocean-floor basalts. Institutul Geological României 9 ALPINE OPHIOLITES OF ROMANIA 87 Fig. 6. — Ti/100 — Zr — 3Y diagram. 1, Codru-Moma ophiolites; 2, Tulcea Zone ophiolites; field A, low-potassium tholeiites; field B, ocean-floor basalts; field C, calc-alkalic basalts ; field D, ocean islands or continental basalts. Fig. 7. — Ti-Cr diagram. 1, Codru-Moma ophiolites; 2. Tulcea Zone ophiolites; LKT, low-potassium tholeiites; OFB, ocean-floor basalts. Institutul Geological României 88 GR. CIOFLICA et al. 10 B. Ophiolites Related to Evoluated Tectonic Settings Ocean- Floor Spreading Related O p hi o Ut e s. The ophiolites of the East Carpathians and the South Carpathians and the basement of the Transylvanian Depression were considered of ocean floor type (Bă du 1 es c u , Săndulescu, 1973). They were formed during the restricted spreading of distinct Carpathian basins and obducted in places during subsequent deformations. According to drilling evidences and geophysical interpretations (Săndulescu, V i s a r i o n, 1979), the western part of the Tran- sylvanian Basin basement contains ophiolites that would representthe relict of an intra-Carpathian basin with oceanic crust. On the other hand, the Hăghimaș-Codru Nappe and the Persani Nappe of the East Carpa- thians that were emplaced during Middle Cretaceous deformations com- prise obducted ophiolites belonging to the above-mentioned basin. The ophiolites of the Hăghimaș-Barau Nappe are characterized by various rocks : peridotite, gabbro, basaltic flows with pillow structure, in places, pyroclastics (Russ o-Săndulescu et al., 19798). They occur as olistholites in the Lower Cretaceous wildflysch or in association with tectonic klippen of the Transylvanian Nappes. The Persani Nappes contain ophiolitic rocks of various kinds, that is serpentinite, gabbro, dolerite, basalt, andesite and alkaline differentiation products (bostonite, trachyte) in close spațial connection with Triassic limestones; both occurrences are restricted to the Lower Cretaceous wildflysch (Patru- lius, 1963 ; C i o f 1 i c a et al., 1965 ; Patrulius et al., 1966). Up to now, there is no available Information about mctallogenesis related to the Transylvanian Depression ophiolites; anyhow, it seems that they lack economic importance. The ophiolitic occurrences related to innermost Flysch Nappes, that is the Black Flysch and the Ceahlău Nappes emplaced during Middle and Upper Cretaceous deformations, seem to belong to the margin of an elongated paleo basin with oceanic crust located in the East Carpa- thians. The significant compression underwent during Cretaceous times is probably responsible for the almost complete consumption of its oceanic crust. In the Black Flysch the ophiolites are represented by basaltic and doleritic spilites (Bleahu, 1962) intimately connected with Middle and Upper Jurassic fine-grained flysch sediments or Uppermost Jurassic- Early Cretaceous mioritic limestones. In the Ceahlău Nappe ophiolites of basaltic type are associated with shales and micrites (Azuga beds) from the lower part of the Sinaia flysch formation (Uppermost Tithonian-Berria- sian). These ophiolites lack metallogenic importance. The same basin that acted somewhere between the South Carpathians and the Moesian Platform gave rise to ophiolites related to the Severin Nappe, that isapproximately the South Carpathian equivalent of the Ceahlău Nappe.The ophiolites of the Severin Nappe consist of basaltic flows and pyro- 8 Arch. I.G.G., Bucharest. Institutul Geological României 11 ALPINE OPHIOLITES OF ROMANIA 89 clastics associated with Lower Sinaia beds and are tectonically emplaced between the Getic Nappe and the Danubian Autochthon (Presacina Zone). These ophiolite occurrences as well as the Flysch Nappes related ophioli- te are to be interpreted as remnants of the marginal areas of this basin. The intensive Upper Cretaceous compression promoted a significant displacement of the Severin Unit which is completely migrated from its root zone; nevertheless the tectonic superposition of two sialic blocks (that is Getic and Danubian Units) provides evidences that collision was reached. Major serpentinite blocks located above the Danubian wild- flysch represent therefore protrusion effects. The ophiolite related metal- logenesis is of Cyprus type and comprises Cu-pyrite massive and stock- work ore at Baia de Aramă. S ub ductio n Related Ophiolites. The widest developed ophiolitic zone of the Carpathians occurs in the South Apuseni Moun- tains. They are related to a complex architecture promoted by strongly compressed structural units that exhibit northward verging thrusts and overthrusts (Lupu, 1975). In fact, the South Apuseni Mountains represent polyphasic tectonic System consequent to pulsatory copressions provided by Cretaceous deformation events; it is also worth mentioning that the great variety of sedimentary facies related to the ophiolite forma- tion reflects the complicate paleotectonic background of the area. Up to the present the oldest sedimentary rocks associated with ophiolites are of Oxfordian age although absolute age determinations (H e r z , Savu, 1974) indicate 180 m.y. for the earliest ophiolites. Upper Jurassic carbonate formations (that is massive limestones of Stramberg type and Aptychus eupclagic limestones) overlie or interfinger the ophiolites. Wi- thin-the Criș, Vulcan, Căpîlnaș, Techereu and Beledeu units (Lupu, 1976) the transition between the ophiolite and the sedimentary rocks is characterized by the following features : pillow lavas — tuffs — jas- pers — mioritic limestones — massive limestones; lavas ± tuffs — cherty limestones — massive limestones; tuffs alternating with micritic limes- tones and grading to micritic, Aptychus limestones; tuffs — jaspers — micritic limestones of Upper Tithonian age — calcareous flysch of Neoco- mian age. Up to now the ophiolites of the South Apuseni Mountains were assigned to the ocean-floor origin (R ă d u 1 e s c u, Săndulescu, 1973; B 1 e a h u , 1974 ; H e r z , S a v u , 1974, ete.); anyhow, Savu (1979) assumed that the upper part of the ophiolites are “inițial calc- alkalic products related to ophiolites” suggesting therefore that ophiolites are always connected with the ocean-floor spreading. On the other hand C i o f 1 i c a and N i c o 1 a e (1980, in press) assigned the ophiolites of the South Apuseni Mountains to the island arc and active marginal basin type ; they resulted from westward subduction of the oceanic crust belon- ging to the Transylvanian Basin which was followed by counterclock notation of the South Apuseni Mountains. A Institutul Geologic al României IGR/ 90 GR. cioflica et al. 12 The various petrographic types of ophiolites found in the Metaliferi Mountains were assigned to the following complexes : — the tholeiitic-prevailing complex, consisting of hyalo-ophitic basaltic flows that exhibit frequent pillow structures, anamesites, sporadic agglomerates and small gabbroic bodies; — the calc-alkalic-prevailing complex, consisting of various flow types and pyroclastic that is andesite, basalt and acidic differentiation products (dacite, rhyolite) and subordinate rocks of alkaiine tendency (limburgite, orthophyre, oligophyre, keratophyre); — the spilitic complex, consisting of spilites and spilitic dolerites. The tholeiitic-prevailing complex is widely developed in the western portion of the Metaliferi Mountains (Droeea Mountains), whereas the calc-alkalic-prevailing complex seat of the Cerbia-Basarabeasa line. The spilitic complex is widespread in the Southern part of the Trascău Moun- tains. The ophiolitie magmatism exhibits a continuous evolution, with some recurrences, from basalts of the tholeiitic complex to basalts with porphyritic texture, andesites, dacites, rhyolites and final products of alkaiine trend. The tholeiitic-prevailing complex and the calc-alkalic-prevailing com- plex represent island arc related ophiolites and the spilitic complex mar- ginal basin ophiolites, according to the following features : — the rather restricted thickness (below 3000 m) of the ophiolites — the lack of the sequential character, that is the ophiolites are depleted of tectonites, cumulates of peridotitic and gabbroic rocks and sheeted dikes; — the compositional range of SiO2 is very wide (37 — 80%), even the SiO2 contents of the tholeiitic-prevailing complex range between 37—55.6% as compared to theocean-floor basalt (47—51 % according to M y i a s h i r o , 1975); — the main bulk of analyses show FeOx/MgO > 1.7 that is charac- teristic of the island arc tholeiites ; — the K2O contents are commonly much higher than those of the ocean-floor basalts which do not exceed 0.4%; — the ubiquitous occurrence of the calc-alkalic products is charac- teristic of the island arc ophiolites. In addition, interpretation of plots in various diagrams (Cioflica, N i c o 1 a e, 1980, in press) show similar evidences listed below : — the Na2O/K2O—(Na2O + K2O) diagram (Fig. 8) exhibits coin- cidences of the above-mentioned three complexes with the island arc volca- nics field of M y i a s h i r o (1975); — major plots in the Ti/Cr diagram (Fig. 9) are located within the low-potassium tholeiite field of island arc character; — major plots occur in the field A (low-potassium tholeiites) and field C (calc-alkalic basalts) of the Ti—Zr diagram (Fig. 10) which repre- sent island arc ophiolites. The spilites were considered marginal basin ophiolites with affini- ties toward the ocean-floor tholeiites ; they are characterized by remar- Institutul Geologic al României igr/ 13 ALPINE OPHIOLITES OF ROMANIA 91 kable petrochemical homogeneity and recurrence to a more basic type as compared to the late island arc ophiolites (Cioflica and N i c ol a e, 1980, in press). A particular feature is provided by the spilites-sediinentary sequence relation in the Feneș beds. The alternation of the spilites and the lime- Nâ2 0 + K 2 0 Fig. 8. — Na20/I<20 — (Na2O + K2O) diagram. 1, tlioleiitic-prevailing complex: 2, calc-alkalic-prevailing complex ; 3, spilitic complex ; 4, field of island arc ophiolites according to Myiashiro (1975). stones'and terrigenous olisthostrome sequence suggests an active marginal basin association. The metallogenic response to the subduction related ophiolites is given by minor Fe-Ti-V magmatic segregations (Căzănești-Ciungani, Almaș-Seliște, Dumbrăvița), Cu-pyrite and pyrite stockworks that resem- Institutul Geological României 32 GR. CIOFLICA et al. 14 ble the Cyprus type (Almășel, Roșia Nouă, Petriș Corbești, Pătîrș), Pb-Zn-Cu deposits of presumably Kuroko type (Vorța), volcano-sedimen- tary Mn deposits (Pîrnești, Godinești, Soimuș-Buceava). complex ; 3, spilitic complex ;for Fig. 9. — Ti-Cr diagram. 1, tholeiitic-prevailing complex ; 2, calc-alkalic-prevailint LKT and OFB see Fig. 7. Fig. 10. — Ti-Zr diagram. 1. tholeiitic-prevailing complex; 2, calc- alkalic-prevaiiing complex; 3. spilitic complex; for A, B, C, D fields see Fig. 5. III. Conelusions The Alpine ophiolites of Romania are related to unevoluated tecto- nic settings, that is short-lived rifts, in the Carpathians and the North Dobrogea orogenic system, and to evoluated tectonic settings, that is ocean-floor spreading zones and subduction zones, in the Carpathians. The major characteristics of the ophiolite setting, magmatism and metal- logenesis are listed in Table. Institutul Geological României TABLE Tectonic scllings for the ophiolile magmatism and metallogcncsis Age | Tectonic empla cement Jurassic Middle Cretaceous Middle and Upper Cretaceous Cretaceous (poly- phasic) Cretaceous (polyphasic) Formation Upper Permian Mideile Triasic Triassic- Jurassic Triassic- Jurassic Middle Jurassic- Lowcr Cretaceous Jurassic- Lower Cretaceous Lower Cretaceous Mineralization orthomagmatic Fc-Ti ores Cyprus type Cu-pyrite ores orthomagmatic Fe-Ti-V ores, Cyprus-like Cu-pyrite ores, Kuroko-like Zn-Pb-Cu ores, volcano-sediinentary Mn ores Magmatism basalt (spilitc) basalt, spilite, dolerite, gabbro ? serpentinite, peridotite, gabbro, dolerite basalt, andesite, trachyte, bosto- 12^ spilile basalt, andesite, dacite, rhyolite and limburgite, orthophyre, keratophyre flows and pyroclastics gabbro small intrusions spilite Occurrence Codru-Moma Mts (Apuseni Mis) Tulcea Zone (North Dobrogea) Western part of the basement of the Transylvanian Basin Hăghimaș-Rarău Nappe and Pcr- șani Nappe (East Carpathians) Black Flysch Nappe and Ceahlău Nappe (East Carpathians) Presacina Zone, Severin Nappe (South Carpathians) South Apuseni Mis Southern part of the Trascău Mts (South Apuseni Mts) Plate lectonie selting Incipient ensialic basin Aulacogen Basin wilh occa nic crust Island arc Active marginal basin pațepi Suțțj!.i poAH-UOtis pat Blaj Suț -pBO-ids .tooțj ueaao pa^pj uoipnpqng pațeniOAOUQ pațvnțOAH 94 GR. CIOFLICA et al. 16 Thus the short-lived rifting is characterized by the significant association of bimodal (ophiolitie-rhyolitic) magmatism, epicontinental sedimentation and syn-diagenetic and epigenetic ore depesition; the ophiolite occurrences lack commonly metallogenic importance. The ocean- floor spreading related setting is marked by Carpathian basins with oceanic crust that were almost completely consumed during various Alpine defor- mation events. Ophiolite occurrences of limited extent represent remnants of their marginal oceanic crust; the metallogenesis is restricted to Cyprus type ores. The subduction related setting exhibit widely developed ophio- lites of island arc and active marginal basin types with associated ortho- magmatic Fe-Ti-V ores, Cyprus-like Cu-pyrite, Kuroko-like Zn-Pb-Cu ores and volcano-sedimentary Mn ores. REFERENCES B 1 ea hu M. (1962) Cercetări geologice în bazinul văii Ruscova (Munții Maramureșului). D.S. Com. Stat Geol. XLV, București. Bleahu M. (1974) Zone (le subducție în Carpații românești. D.S. Inst. geol. geofiz.,LX, București. C i o f 1 i c a GPatrulius D ., I o n c s c u J a n a , U d u b a ș a G. (1965). Ofiolitele allolitone triasice din Munții Persani. Stud. cerc. geol. geofiz, geogr-, seria geol-, 10,1, București. C i o î 1 i c a G ., N i c o 1 a e I . (1980) The Origin, Evolution and Tectonic Setting of the Alpine Ophiolites from the South Apuseni Mountains (in press). Herz N., Savu H. (1974) Plate Tectonics History of Romania. Geol. Soc. Ann. Bull., 85, Colorado. Ia novici V., Borcoș M ., Bleahu M., Patrulius D., Lupu M., Dimi- trescu R., Savu II. (1976) Geologia Munților Apuseni. Edit. Acad. R.S.R., București. L u p u M. (1975) Einige Benierkungen zur Tektonik des Ziidlichen Apuseni Gebirges (Sieben- burgisches Erzgelinge). Rev. Rotim. Geol. Geophys. Geogr-, serie de Geologie, 19, București. Lupu M. (1976) The Main Tectonic Features of the South Apuseni Mountains, Rev. Rotim. Geol. Geophys. Geogr., scrie de Giol-, 20, București. Myiashiro A. (1975) Classification, Characteristics and Origin of Ophiolites. Journ. Geol., 83. Patrulius D. (1963) Le Wildflysch et les olistolilhes des Monts Perșani. Ass. Geol .Carp.- Balc., VI Congres (Varsovie-Cracovie). Besumi des comunications. Varsovie. P a t r u 1 i u s D., P o p a E 1 e n a , Popescu Ileana (1966) Seriile mezozoice autoh- tone și pînza de decolare transilvană in împrejurimile Comanei (Munții Perșani). An. Com. Geol. Rom., XXXV. 397 — 3 141, București. Pearc e .1. A., Cann J. R. (1973) Tectonic Setting of Basic Volcanic Rocks Determi- ned Using Trace Elements Analysis . Earlh a. Planelary Sci. Leit., 19, 290—300, Amsterda m. a Institutul Geological României Vigrz 17 ALPINE OPHIOLITES OF ROMANIA 95 Pearce J. A., Gale G. H. (1976) Identification of Ore Deposition Environment from Trace Element Geochemistry of Associated Igneous Hbst Rocks. The Geol. Soc. of London Proc. Joint. Meet. Voie. Slud. Group of IheG.L.F. and London, 21—22 .Ian. 1976. Rădulescu D., Săndulescu M. (1973) The Plate Tectonic Concept and the Geolo- gical Structure of the Carpathians. Teclonophysics, 16, 155 — 161, Amsterdam. R u s s o - S ă n d u 1 e s c u Doina, Udr eseu Constanța, Medeșan Ale- xandra (1981) Cercetările petrochimice ale ofiolitelor mezozoiee din sinclinahil marginal Rarău-Hăghimaș. D. S. Inst. geol. geofiz., LXVI/1 (in press). Savu H. (1980) Genesis of the Alpine Cycle Ophiolites from Romania and Their Associated Calc-Alkaline and Alkaline Volcanics. An. Inst. geol. geofiz., LVI, București. Savu H., Udr eseu Constanța, Nea c șu V a s i 1 i c a (1980) Structural, Petrolo- gie, Geochimic and Genetic Study of the Ophiolites in Niculițel Zone (North Dobrogea). D.S. Inst. geol. geofiz. LXV/1, București (in press). Savu H., Udrescu Constanța, Neacșu Va silica (1981) Structura și geneza diabazelor din zona Luncavița-lsaccea-Mănăstirea Cocoș (Dobrogea de nord). D.S. Inst. geol. geofiz., LXVII/1 (in press). Săndulescu M., V i s a r i o n M. (1978) Considera tions sur la structure tictonique du soubassement dc la Depression de Transylvanie, D. S. inst. geol. geofiz., LXIV/5, 153 — 173, București. Stan N., Udrescu Constanța (1980) L’etude petrochimique des roches spilitiques des., Monts Codru-Moma. Leur genese. Bev. Foum. Geol. Geophys., serie Geologie (in press). Vlad Ș. (1978) Metalogeneza triasică din zona Tulcea. Stud. cerc. geol. geofiz. geogr. (geol.), 23, București. Institutul Geological României Institutul Geological României CORRELATION DES DINOFLAGELLES AVEC LES ZONES D’AMMONITES ET DE CALPIONELLES DU CRETACE INFERIEUR DE ȘVINIȚA - BANAT 1 PAR EMANUEL ANTONESCU, EMIL AVRAM2 Dinoflagellata. Ammonoidea. T iniinnidaea. Loiver Cretaceous. Biozones. Biostratigrapic correlation ; South Carpathians — Danubian Domain sedimentari/ — Soinița-Svinecea Zone. Abstract Dinoflagellate — Am menite — Tintinnid Correlation in the Lower Cretaceous from Svinița region (Banat, Romania). Some biozones, founded on the vertical succession of the dinoflagellate assemblages within the Lower Cretaceous deposits from Svinița (Banat) are proposed. These biozones were framed to the Lower Cretaceous stratigraphical scale on the ground of correlation with the Calpionellid zones and Cephalopod assemblages identified within the same strata, as follows : (1) a biozone with Druggidium apicopaucicum and Phoberocysta neocomica (Upper Berriasian — Valanginian); (2) a bizone with Oligosphaeridinium complex and Druggidium deflandrei (Hauterivian); (3) a biozone with Dingodinium albertii and Meiourogonyaulax sloveri (Lower Barremian) and (4) a biozone with Prolixosphaeridium parvispinum (Upper Barremian — Lower Aptian). It is also possible to recognise within the biozone with Druggidium apicopaucicum and Phoberocysta neocomica (1) : a lower part — with Druggidium apicopaucicum (Upper Berriasian — Lower Valanginian), and an upper part — with Oligosphaeridium asterigium, Polysphaeridium ivar- reni and Biorbifera johnewingi (middle Lower Valanginian — Upper Valanginian). I. INTRODUCTION La region de Svinița est depuis longtemps connue pour la richesse en ammonites des depots duCretace inferieur. Les travaux de Kuder- n a t s c h (1852), T i e t z e (1872), U h 1 i g (1883), S c h a f a r z i k 1 Note rețue le 21 marș, 1980 et acceptăe pour publication le 25 marș, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. 7 — c. 658 Institutul Geological României \IGR 98 EM. ANTONESCU, E. AVRAM 2 (1894), K iii an (1907—1913), Koch (1912), Răileanu (1953, 1960), Răileanu et al. (1964, 1969), Bo 1 d or& A v r a m (1972), Avram (1976), en temoignent. Les calpionelles des memes depots ont ete inventoriees par Ru.su (1970), Avram (1976, et etude en cours). La richesse de la faune et le caractere petrographique des formations — calcaires en plaquettes bien litees, marnocalcaires, marnes et argi- les — rendaient cette region intdressante pour une etude des dinoflagel- les, afin de precisei- la repartition stratigraphique du microplanctou vege- tal, en corrdlation avec les ammonites et les calpionelles. II. STRATIGRAPHIE, ZONES D’AMMONITES ET ZONES DE CALPIONELLES DES FORMATIONS DE MURGUCEVA ET SVINIȚA Les depots du Cretace inferieur de la region de Svinița sont repre- sentes en principal par les formations de Murguceva et Svinița ; il y a en outre une formation d’âge albien, mais celle-ci sort du cadre de ce travail. La region de Svinița fait pârtie de la zone de sedimentation de Sirinia (Codarcea, 1940), respectivement du «sillon de Svinița» (Pop, 1973) ou du « sillon interne » (Năstăseanu, 1979) de l’au- tochtone danubien des Carpathes Meridionales. Les d6p6ts eocretaces de la. region de Svinița sont en continuite de sedimentation avec ceux du Tithonique terminal, dans un meme paquet de calcaires blancs ă accidents siliceux, denommepar A v r a m (1976) — — formation de Murguceva. A la formation de Murguceva font suite en continuite de sedimen- tation des calcaires marneux grisâtres et ensuite des marnocalcaires, marnes et argiles. Ces depâts ont ete designes par Răileanu (1953) sous le nom « couches » de Svinița et par Avram (1976) comme for- mation de Svinița. A. Formation de Murguceva (Tithonique superieur-Hauterivien) La formation de Murguceva repose en discontinuite de sedimen- tation sui- les calcaires noduleux grisâtres, verdâtres et rouges du Juras- sique superieur. La pârtie basale de la formation est constituee pai' des calcaires faiblement noduleux, ă rares accidents siliceux, en alternance avec des calcaires compacts et des calcarenites (ruisseaux Murguceva, Munteana, vall6e de la Sirinia) ou par des calcaires blanchâtres, compacts, ă accidents siliceux (Pîrîul Morilor). La plus grande pârtie de la formation est constituee par des calcai- res plus ou moins fins, gris clair, blancs sur les surfaces d’alteration, cas- sants, en couches de 10 ă 30 centimetres, sdpards par des calcaires schis- teux qui forment des intercalations de 5 â 10 centimetres. Les surfaces de stratification sont enveloppees par des pellieules d’argile et presentent parfois des traces de dissolution. Ces calcaires contiennent des accidents siliceux distribues d’une maniere irreguliere â l’interieur des couches plus epaisses. Institutul Geological României 3 dinoflagellEs du CRETA'CE inferieur de svinița 99 La limite superieure de la formation de Murguceva a etd tracee par Avram (1976) au niveau ou les accidents siliceux disparaissent. Aux alentours du village de Svinița, ce niveau se situe lâ oii les calcaires blancs passent graduellement â des calcaires sublitographiques, sombres, avec intercalations de schistes marneux gris-noirâtre (Pîrîul Morilor). En dehors de la region etudide, dans le bassin hydrographique de Sirinia, ces intercalations schisteuses font leur apparition plus bas, c’est-ă-dire au-dessous du niveau sommital â accidents siliceux. L’epaisseur de la formation de Murguceva varie entre 100 et 150 metres. Tout comme dans le Neocomien des chaînes subalpines (Th ie- 1 o y, 1965), des « slump-packets » et des indices de ravinement sont pre- sents sur quelques-unes des coupes au moins (par exemple, sur le versant gauche du ruisseau Murguceva — pl. I, l’intervalle M015—M025). La plus grande pârtie de Ia zone d’affleurement se situe en dehors de la region etudiee, notamment dans le bassin de la valide de Sirinia. Les affleurements qui font l’objet du present travail se trouvent le long du ruisseau Mur- guceva et du Pîrîul Morilor. B. Formation de Svinița (Hauterivien superieur-Aptien inferieur) A v r a m (1976), se basant sur les travaux de E ă i 1 e a n u (1953, 1960), mais avec observations complementaires, a separe dans Ie cadre de la formation de Svinița une sous-formation inferieure — la sous - formation de Pîrîul Morilor (Hauterivien superieur-Barrdmien inferieur) comprenant les « couches calcaires schisteuses en plaquettes ă intercala- tions marneuses » (E ă i 1 e a n u, 1953) et une sous-formation supd- rieure — la sous-formation de Temeneacia (Barremien inferieur ter- minal-Aptien inferieur), comprenant «le paquet des schistes calcaires marneux » et «le paquet des marnes grises » (E ă i 1 e a n u, 1953) ou « marnes de Svinița » (B o 1 d o r, S t ă n o i u & S t i 11 ă, 1963 3). La sous-formation de Pîrîul Morilor comporte des calcaires subli- thographiques sombres en alternance avec des marnes schisteuses et, progressivement plus rares, des calcaires blancs semblables â ceux de la formation de Murguceva, mais sans accidents siliceux. Vers le sommet de la sous-formation de Pîrîul Morilor, les intercalations de calcaires marneux deviennent dominantes. L’epaisseur' de la sous-formation est de 30 â 35 metres sur la coupe de Pîrîul Morilor; les meilleurs affleurements sont ceux du Pîrîul Morilor, de la route Orșova-Svinița au Nord-Ouest de l’em- bouchure du ruisseau Murguceva, et aussi â l’embouchure de la valide de Sirinia. La sous-formation de Temeneacia comprend des altemances de mar- nes plus ou moins schisteuses, de marnoargiles et de mamocalcaires som- bres, bleuâtres ou blanchâtres sur les surfaces d’alteration, avec inter- calations de calcaires marneux. Cette sous-formation affleure de fașon assez discontinue Ie long du Pîrîul Morilor, sur la route Orșova-Svinița, au voisinage drt rdservoir d’eau de Svinița, sur le ruisseau Temeneacia --------------- . .J&u.J 3 Arch. I.G.P.S.M.S., București. \ IGR> Institutul Geological României 100 EM. ANTONESCU, E. AVRAM 4 et sur le Pîrîul Țiganilor. Son ^paisseur ddpasse 80 metres en jugeant d’apres la coupe de Pîrîul Morilor, ă laquelle viennent s’ajouter les affleu- rements de la route Orșova-Svinița et ceux de la rive gauche du Danube, ă proximit6 du debarcadere de Svinița. C. Associations de calpionelles et de eephalopodes Parmi les nombreuses coupes des dâpots eocretac6s de la region de Svinița, nous avons choisi pour ce travail celles qui offraient les ele- ments les plus nombreux pour une corr61ation calpionelles-cephalopodes- dinoflagellds, notamment : 1) le versant droit du ruisseau Murguceva (pl. I, MO1-MO50) pour la pârtie inferieure de la succession; 2) la coupe du Pîrîul Morilor (pl. II, VI—VII) conținuse sur la route Orșova-Svinița (D) jusqu’au debarcadere de Svinița (SI) pour l’intervalle Hauterivien- Aptien inferieur; 3) les coupes du ruisseau Temeneacia (S4) et du Pîrîul Țiganilor (TI—T8) pour l’intervalle du Barremien superieur. 1. Associations de calpionelles Nous allons presenter les zones de calpionelles seulement dans la coupe de Murguceva, ou, dans les niveaux correspondants, nous avons trouve des dinoflagelies (dans l’intervalle de MO21-MO41, c’est-â-dire les echantillons 7341—7495, pl. I); pour plus de details sur la repartition de ces zones sur le ruisseau Morilor et dans le reste de la region de Svinița, voir Avram (1976). Zone â Crassicollaria La zone ă Crassicollaria (Tithonique superieur) apparaît seulement dans la coupe de Murguceva (sur le Pîrîul Morilor elle faisant defaut); cette zone est repr6sent6e imm6diatement au-dessus de la limite entre les calcaires noduleux (qui contiennent seulement des Saccocoma) et les calcaires sombres. Elle comprend : Crassicollaria intermedia (D u r a n d- Delgas), O. brevis (E e m a n e), C. massutiniana (C o 1.), C. parvula (E em a n e). Son 6paisseur ne dăpasse pas 2—3 metres (MO3—MO4). Zone a Calpionella alpina La zone ă Calpionella alpina ddbute avec des calcaires d^tritiques ayant environ 12 metres dApaisseur (MO5—MO16); â la pârtie inferieure elle comporte de nombreuses Calpionella alpina L o r e n z, associees â Tintinnopsella carpathica (Murgeanu & Filipescu). A l’inter- valle qui lui revient fait suite un paquet glisse (MO11—MO16), dont l’association de calpionelles comprend les especes de la zone Crassicol- laria et en outre C. alpina et T. carpathica. La zone â Calpionella alpina correspond ă l’intervalle du Tithoni- que terminal-Berriasian inferieur. Institutul Geological României 5 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINITA 101 Zone ii Calpionellopsis Cette zone est repr^sentee sur Ia coupe de Murguceva dans les memes calcaires â. accidents siliceux (MO17—MO21), au-dessus du paquet glissâ qui renferme C. alpina et des Crassicollaria. Dans son intervalle, epais de 12 metres, il y a Calpionellopsis simplex (Col.), C. oblonga (C a d i s h) et aussi C. alpina, T. carpathica, T. longa (Col.), Calpio- nellites murgeanui (P o p), Remaniella cadishiana (C o 1.), P. daday K n a u e r. Cette zone est censee representer le Berriasien superieur. Zone ii Calpionellites La zone ă Calpionellites darderi (Col.) va du niveau MO22 au niveau MO35. L’intervalle stratigraphique qui lui revient est d’environ 27 metres ; un deuxieme paquet glisse (MO22—MO25, pl. I) lui fait suite. En dehors de l’espece index, il y a C. oblonga, C. murgeanui, T. carpathica, T. longa, R. dadayi, R. cadishiana. Lorenziella hungarica K n a u er. Cette zone correspond au Berriasien superieur terminal et ă la plus grande pârtie du Valanginien. 2. Association d’ammonites Les c6phalopodes prelevees de la pârtie inferieure de la formation de Murguceva sont relativement rares. Sur le versant droit du ruisseau Murguceva, seul l’intervalle de la zone Calpionellopsis a livr6 quelques ammonites entre 15 et 23 metres au-dessus de la base de la formation notamment : Spiticeras sp. ex. S. polytroptychum U h 1 i g, Ptycho- phylloceras pt-ychoicum (Qu.), dans les niveaux MO16—MO17, et Fau- riella sp. ex gr. F. boissieri Pict et (dans MO20—MO21), especes qui indiquent un Berriasien inferieur. Plus haut, dans la zone â Calpionellites, nous avons preleve du niveau MO25 Kilianella aff. roubaudiana d’O r b. et du niveau MO28 K. roubaudiana retrocosta S a y n., especes propres ă la zone ă Kilianella roubadiana du Valanginien inferieur. Plus haut encore (pl. I, MO31—MO34), ă 40 metres au-dessus de la base, il y a Olcostephanus cf. catulloi (R o d i g i e r o) et, ă 50 metres au-dessus de la base, O. cf. sayni (K i 1 i a n) — niveau dans lequel dis- paraissent les calpionelles, donc appartenant au Valanginien superieur. Sur la meme coupe, nous considerons que la limite Valanginien-Hauteri- vien est situee au niveau MO41 immediatement au-dessous du niveau d’apparition du Neocomites (Teschenites) pachydicranus Th i eu 1 o y. Zone a Crioceratites duvali Dans la coupe du Pîrîul Morilor (pl. II, VI—V3) et aussi au sommet du versant droit du ruisseau Murguceva (MO47 —MO50) une zone ă Crio- ceratites duvali L e v. a 6t6 mise en evidence â la pârtie superieure des 102 EM. ANTONESCU, E. AVRAM 6 calcaires blancs â accidenta siliceux, sur environ 30 metres d’epaisseur. En dehors de l’espece index, ont ete identifies de nombreux Crioceratites parmi lesquels C. matsumotoi ( S a r k a r), C. mandovi nom. nov. (= C. villersianum var. bituberculata S a r k a r), C. nolani (K i 1 i a n), C. majoricensis Noian et aussi Paraspinoceras pulchervimum (d’Orb.) et Spitidiscus ci .incertus (d’O r b.). Cette zone est egalement reprâsentee dans la coupe du Pîrîul Morilor, sur environ 5 metres, â la pârtie inferieure de la sous-formation de pîrîul Morilor (formation de Svinița). Cette biozone correspond â l’Hauterivien moyen (zone ă Criocera- tites loryi — Olcostephanus jeannoti et zone â Subsaynella sayni). Zone a Acrioeeras seringei et Paraspinoceras jourdani La biozone ă Acrioeeras seringei (A s t i e r) et Paraspinoceras jour- dani (A știe r) occupe un intervalle de 12 metres sur la coupe du Pîrîul Morilor au-dessus de la biozone ă Crioceratites duvali (pl. II, V4—V7/2). Elle comporte, ă cote des especes index, Crioceratites nolani (K i 1.), C. basseae (Sarkar), O. sornayi (Sarkar), C. ballearis (Noian), O. emerici Lev., C. duvali, Buptychoceras inornatum (S i m,). Hamulina astieriana d’ O r b., Duvalia dilatata majoriana S t o y a n o v a-V e r- g i 1 o v a. Cette biozone represente la pârtie terminale de l’Hauterivien su- perieur. Zone a Paraspiticeras et Pseudothurmannia La zone ă Paraspiticeras et PseudotJiurma/nnia est representee sur le Pîrîul Morilor par environ 15 metres de depots de la sous-formation de Pîrîul Morilor (pl. II, V7/3—V8/3). Elle contient d’une part Pseudothur- mannia cf. belimelensis Dimitro va, P. cf. pseudomalbosi (S a r. & S c h o n d.) et quelques metres plus haut, P. cf. angulicostata (d’O r b.), P. picteti Sar ka r, P. cf. catuloi (P a r o n a); Paraspiticeras paclvy- cyclus (Uhlig), P. guerinianum (d’Orb.). Aux especes mentio- nees ci-dessus s’ajoutent Crioceratites tHiollierei A s t i e r, Barremites sp., Melchâorites sp., et aussi, ă la pârtie superieure de la biozone (V8/3), Psilotissotia favrei (Ooster). A l’exemple de Muller & Sehenk (1943), Patru lius (1969), Breskowski (1973), Avram (1976), Patrulius& Avram (1976) et partiellement dans l’acception de Lapeyre& Tho mei (1974), nous considerons cette biozone comme repr&entant la base du Barremien. Zone a Pulchellia ex gr. compressissima, Spitidiscus, Holcodiscus et Leptoceras Sur le Pîrîul Morilor, au-dessus de la zone ă Paraspiticeras et Pseudo- thurmannia, ă la pârtie basale de la sous-formation de Temeneacia, il y a un intervalle avec de nombreux exemplaires de Barremites et Melcltio- rites. de rares Leptoceras (pl. II, V8/5). C’est leur pr^sence qui permet de Institutul Geological României 7 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 103 correler cet intervalle avec celui du reservoir d’eau du village Svinița (voir A vr a m, 1976), qui eonstitue le principal affleurement de la bio- zone. Cette biozone correspond ă la pârtie terminale du Barremien in- ferieur. Biozone non-definie Cette biozone non-definie, qui debute ă la pârtie inf^rieure de la sous-formation de Temeneacia avec l’appartition de l’espece Silesites seranonis (d’O r b.) et qui continue jusqu’â l’apparition du geme Ime- rites, comprend de nombreuses especes avec une grande extension dans le Barremien superieur. Sur le Pîrîul Morilor elle a offert (pl. II, V9) entre autres : Lytoceras phestum Math., L. rarinctum Uhlig, Costidiscus (Costidiscus) recticostatus (d’O r b.), Costidiscus (Macroschaphites ) yvani (Puzos), Silesites seranonis (d’Orb.). Zone a Imerites et Eristavia La zone â Imerites et Eristavia a ete mise en evidence dans la coupe du Pîrîul Morilor (pl. II, VII) et sur le ruisseau Temeneacia (fig. 4, S4). Les especes caracteristiques de cette biozone sont: Imerites giraudi (K i 1.), Imerites girau dimulticostatus T o u b., Eristavia dichotoma (E ryi- s t a v i); ensemble avec celles-ci il y a Lytoceras phestum, Costidiscus (Costidiscus) recticostatus, Silesites seranonis, S. seranonis trajani, Mel- chiorites cf. seguensae ( C o q.), 31. melchioris, « Barremites » streptosoma, Pseudohaploceras tachtaliae. La biozone a Imerites et Eristavia correspond approximativement â la pârtie moyenne du Barremien superieur. Zone ă « Crioceratites » ex gr. barremense-orbignyi Cette biozone mise en evidence sur le Pîrîul Țiganilor (pl. III, TI — —T8) comprend les especes index « Crioceratites » cf. orbignyi (M a t li e- r o n in H a u g, 1889), « C. » aff. barremense (K i 1 i a n) et aussi Lytoceras phestum, Costidiscus (Costidiscus) recticostatus, C. tardus A v r a m Silesites seranonis C. (C.) olcostephanoides Uhlig, des especes de Hamulina, Barremites, Melchiorites etc. (voir Avram, 1976). La biozone â « Crioceratites» ex gr. barremense — orbignyi â une position encore discutable dans la succession des depots du Barremien superieur, par rapport â la biozone a Imerites et Eristavia. Sa position â la pârtie terminale du Barremien superieur se justific par le fait que des exemplaires de Beshayesites ont ete mentionn^s sur le Pîrîul Țiganilor (Eâileanu et al., 1969 ; Co dare ea, in coli.). Toutefois, les nou- veaux prelevements d’echantillons effectues les dernieres ann^es n’ont pas confirme la presence de ce geme. i Institutul Geologic al României \ igr/ 104 EM. ANTONESCU, E. AVRAM 8 Zone a Pseudohaploceras matheroni et Deshayesites weissi La biozone ă Pseudohaploceras matheroni (d’ O r b.) et Deshayesites weissi (N e u m ay r&Uhlig), de l’Aptien inferieur (Bedoulien infe- rieur), a ete mise en evidence preș du debarcadere de Svinița (fig. 4, SI et dans le deblai de la route Orșova-Svinița-Moldova Nouă au Nord du pont sur le Pîrîul Morilor (pl. III, D); son association comprend egalement Costidiscus (Costidiscus) recticostatus, Procheloniceras ex gr. albrechti- aiistriae (H o h e n e g g e r in U h 1 i g). III. DISTRIBUTION STRATIGRAPHIQUE DES DINOFLAGELLES DANS LES FORMATIONS DE MURGUCEVA ET SVINIȚA Nous allons presenter tout d’abord la classification des especes de dinoflagelies et des acritarches que nous avons identifies jusqu’ă present dans les formations de Murguceva et Svinița (planches IV—XIV), con- formement ă la classification etablie par Sarjeant&Downie (1974); il faut mentionner que cette classification n’est pas definitive, de nouveaux genres ayant ete decouverts par la suite. D’autre part, certains auteurs preferent grouper les dinoflagelies selon les affinites avec les grands groupes de dinoflagelies actuels — Gonyaulacacean Group, Peri- diniacean Group (D a v e y & V er d i er, 1973); D u x b u r y, 1977), ou selon l’archeopyle et en ordre alphabetique (Stover & E v i 11, 1978); pour le moment, nous le repetons, nous utilisons la classification de Sarjeant &Downie (1974). A. Classification des dinoflagelies des formations de Murguceva et Svinița » Classe Dinophyeeae P a s c h e r Sous-classe Diniferophyceae B e r g h. Ordre Peridiniales S c h u 11, 1869 Familie Gonyaulacystaceae S a r j e a n t & D o w n i e, 1966, emend. S a r j e a n t & D o w n i e , 1974 Genre Cribroperidinium N e a 1 e & S a r j e a n t, 1962, emend. D a v e y, 1969 Cribroperidinium sp. Cribroperidinium orthoceras (E i s e na c k) D a v ey, 1969 Genre Druggidiuin Hab ib, 1973 Druggidium apicopaucicum H a b i b, 1973 (Berriasien—Barremien) Druggidium deflandrei (M i 11 i o u d) Ha b i b, 1973 (Berriasien- Albien) Genre Gonyaulaeysta Deflandre, 1964, emend. Sarjeant in Davey, Downie, Sarjeant & Williams, 1966. Gonyaulaeysta cf. diutina D u x b u r y, 1977 (Berriasien-Hauteri- vien) 9 DINOFLAGEULES DU CRETACE INFERIEUR DE SVINIȚA 105 Gonyaulacysta sp. A Gonyaulacysta sp. B Gonyaulacysta sp. C Genre Leptodinium K 1 em en t 1960, emend. Sar j ea ut in Davey, D o w n i e, Șarje a nt & Williams. 1966 cf. Leptodinium sp. Genre Millioudodinium Stover & E v i t t, 1978 cf. Millioudodinium sp. Genre Oceisueysta G i t m e z, 1970 Oceisueysta sp. ex G i t m e z, 1970 Oceisueysta tentoria Duxb u r y, 1977 (Berriasien—Barremien) Dinoflagelle type A Familie Apteodiniaeeae E i s e n a c k, 1961, emend. Sar j eant & Downie, 1972 Genre Apteodinium E i s e n a c k, 1948. Apteodinium cf. conjunetum Eisenack & C o o k s o n, 1960 Genre Tapeinosphaeridium loannides, S t a v r i n o s & Downie, 1976 Tapeinosplweridium perichompsum loannides, Stavrinos & Downie, 1976 Tapeinosphaeridium cf. granulatum loannides, Stavri- nos & Downie, 1976 Genre Xenieodinium Element, 1960 cf. Xenieodinium densispinosum K1 em ent, 1960 FamilieMicrodiniaceae Eisenack, 1964, emend. Sar j eant & D o wni e, 1972 Genre Meiourogonyaulax S a r j eant, 1966 Meiourogonyaulax stoveri M i 11 i o u d, 1969 (Eimmeridgien? — Aptien) Familie Formeaceae Sarjeant & Do vni e 1966, emend. S ar- jeant & Downie, 1974 Genre Fromea C o o k s o n & Eisenack, 1958 Fromea amphora Cookson & Eisenack, 1958 Genre Wallodinium Loeblich & Loeblich, 1968 Wallodinium krutzschi (Alberti) Habib, 1972 (Berriasien— Barremien) Familie Canningiaeeae Sarjeant & Downie, emend. Sar- jeant & Downie, 1974 Genre Chytroeisphaeridia Sarjeant, 1962 Chytroeisphaeridia chytroeides (Sarjeant) Downie & Sar- jeant, 1965 Geme Sentusidinium Sarjeant & Stover, 1978 cf. Sentusidinium? atlaniicum (Habib) Sarjeant & Sto- ver, 1978 Sentusidinium sp. A Sentusidinium sp. B. 106 EM. ANTONESCU, E. AVRAM 10 Sentusidinium ? sp. C Sentusidinium sp. D Genre Cyclonephelium (Deflandre & C’ookson) Evitt & S t o ver, 1978 Cyclonephelium distinctum D e f 1 a n d r e & C o o ks o n, 1955 cf. Cyclonephelium hystrix (E i s e n a c k) Sarjeant &Stover, 1978 Familie Broomeaceae Eisenack, 1969, emend. Sar j ea n t & D o w n i e, 1974 Genre Batioladinium Brideaux, 1975 Batioladinium sp. Genre Broomea L e n t i n & Williams, 1976 Broomea^t sp. Familie Ctenidodiniaeeae S a r j e a ut & D o w n i e, 1966, emend. Sarjeant & D o wni e, 1974 Genre Ctenidodinium Deflandre 1938, emend. Sarjeant, 1966 cf. Ctenidodinium elegantulum M i 11 i o u d, 1969 (Valanginien — Barremien) Familie Spiniîeritaeeae S a r j ea nt, emend. Sarjeant & D o w n i e, 1974 Genre Spiniîeritaeeae M a n t e 11, 1850, emend. Sarjeant, 1970 Spiniferites ramosus (E h r e nb er g) M a n t e 11, 1854 Spimferides dentatus (G o c h t) Lentin& Williams, 1973, emend. Duxbury, 1977 Geme Achomosphaera Evit t, 1963 Achomosphaera neptuni (Eisenack) D a v e v & Williams, 1966 Genre Ilystrichodinium (Deflandre) Sarjeant, 1966 Hystrichodinium voigti (Alberti) Clarke&Verdier, 1969 Familie Deîlandreaceae (Eisenack) Sarjeant & Do wnie, 1974 Genre Dingodinium C o o k s o n & Eisenack, 1958 Dingodinium albertii Sarjeant, 1956 (Tithonique—Albien) Familie Pseudoeeratiaeeae (Eisenack) Sarjeant & Do w- n i e, 1966 Genre Pseudoeeralium G o c h t, 1957 Pseudoeeralium pelliferum G o c h t, 1957 (Berriasien—Barremien) Genre Odontochitina (Deflandre) Davey, 1970 Odontochitina operculata (O. We t z el) D ef la ndne & C o o k- s o n, 1955 Familie Muderongiaeeae (N ea 1 e & Sarjeant) Sarjeant & D o av ni e, 1966 Geme Muderongia Co o ks o n & Eisen ack, 1958 Muderongia staurota S a r j e a n t, 1966 Muderongia sp. cf. M. mcwhaei Cookson & Eisenack, 1958 ex Wall & Evitt, 1975 Institutul Geological României 11 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 107 Muderongia tomaszowensis Albe r t i, 1961 Geme Phoberoeysta AI i 11 i o u d, 1969 Phoberoeysta neocomica (Goeht) ĂI i 11 i o u d, 1967 (Berriasien— —Aptien) Familie Hystriehosphaeridiaceae (E v i 1t) S a r j e a n t & D o w n i e, 1974 Genre Oligosphaeridium D a v e y & Williams, 1966 Oligosphaeridium complex (W h i t e) Davey & Williams în Davey, D o w n i e, Sarjeant & Williams, 1966, (debut Va- langinien) Oligosphaeridium asterigium (Goeht) Davey& Williams, in D a v e y, D o w n i e, Sarjeant & Williams, 1966, (Valan- ginien —Barremien) Oligosphaeridium cf. diastema Singh, 1971 Geme Tanyosphaeridium Davey & Williams, 1966 Tanyosphaeridium sp. A Tanyosphaeridium sp. B. Familie Exoehosphaeridiaceae Sarjeant & D o w n i e, 1966 Genre Cometodinium Def landr e & Co ur t e vi 11 e, 1939 Cometodinium 1 sp. Familie Cordosphaeridiaceea Sarjeant & D o w ni e, 1974 Geme Kleithriasphaeridium Davey, 1974 Kleithriasphaeridium fasciatum (Davey & Williams)Davey, 1974, (Berriasien—Barremien) Familie Systematophoraeeae Sarjeant & Downie, 1974 Genre Amphorula D o d e k o v a, 1969 cf. Amphorula metaelliptica D o d e k o v a, 1969. (Tithonique— Berriasien) Genre Coronifera C o o k s o n & Eisenack, 1958 Coronifera oceanica C o o k s o n & Eisenack, 1958 Genre Prolixosphaeridium (Davey, D o w n i e, Sarjeant & Williams) Davey, 1969 Prolixosphaeridium parvispinum (D e f 1 a n d r e) D a v e y, D o w- n i e, S a r j e a n t & W i 11 i a m s, 1966 (= ? Prolixosphaeridium. dei- rense D av ey, D o w n i e, Sarjeant & Williams, 1966 ; Ju- rassique ? — Vraconien). Prolixosphaeridium 1 sp. A. Familie Cleistosphaeridiaceae Sarjeant & D o w n i e, 1974 Genre Cleistosphaeridium Sarjeant & D o w n i e, 1974 Cleistosphaeridium 1 sp. A Genre Polysphaeridium Davey & Williams, 1966 Polysphaeridium warreni Habib, 1976 (Berriasien—Barremien) Polysphaeridium. ci. laminaspinosum Davey & Williams, 1966 Familie Adnatosphaeridiaceae Sarjeant & D o wn i e, 1966 Genre Adnatosphaeridium Williams & D o w n i e, 1966 cf. Adnatosphaeridium sp. Familie Lingulodinilaceae Sarjeant & D o w n i e, 1974 Institutul Geologic al României \ 16 R / 108 HM. ANTONESCU, E. AVRAM 12 Geme Operculodiniuni W a 11, 1967 Operculodinium sp. A. Familie Florentiniaceae Harker & Sarjeant, 1975 Geme Florentinia D a v e y & V e r d i e r, 1973 Plorentinia cf. mantelli (D a v e y & Williams in D a v e y et al., 1966) Da v ey & V e r d i e r, 1973 Familie Incertae Genre Biorbifera Hab ib, 1972 Biorbifera johnewingi H a b i b, 1972 (Berriasien—Valanginien moyen) Biorbifera sp. A Geme Silieisphaera D a v e y & V e r d i e r, 1970 cf. Silieisphaera sp. Genre Subtilisphaera J a i n & M i 11 e p i e d, 1973 Subtilisphaera cf. perlucida (A 1 b e r t i) Jain&Millepied, 1973 Genre Cassiculosphaeridia D a v e y, 1969 Cassiculosphaeridia magna D a v e y, 1974 Groupe Aeritareha Evit t, 1963 Sous-groupeAcanthomorphitae Downie, Evitt & Sarjeant, 1963 Genre Baltisphaeridium (Eisenack) Downie & Sarjeant, 1962 Baltisphaeridium sp. B ex Singh, 1972 Sous-groupe Herkomorphîtae Downie, Evitt&Sarjeant, 1963 Geme Cymatiosphaera (O. W e t z e 1) D e f 1 a n d r e, 1954 Cymatipshaera pach/ytheca Eisenack, 1957 Sous-groupe Pteromorphita Downie, Evitt&Sarjeant, 1963 Genre Pterospermopsis W. W e t z e 1, 1952 Pterospermopsis eurypteris Cookson & Eisenack, 1958 Pterospermopsis harți Sarjeant, 1960 Pterospermopsis aureolata Cookson & Eisenack, 1958 cf. Pterospermopsis sp. Pterospermopsis cf. australiensis D ef 1 a n d r e & Cookson, 1955 B. Distribution des dinoflagelles dans la formation de Murgueeva Le premier niveau qui contient des dinoflagellfe dans la formation de Murgueeva est le niveau MO21/7341 (pl. I), situ6 dans la zone ă Cal- pionellopsis ă proximite immediate de la limite avec la zone â Calpionel- lites, donc preș de la limite Berriasien—Valanginien. L’assoeiation com- prend : Chytroeisphaeridia chytroeides Cometodinium^ sp. Druggidium apicopaucicum DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 13 109 Dinoflagelle type A Gonyaulaeysta sp. A. Gonyaulaeysta cf. diutina Muderongia cf. tomaszowensis Occisucysta sp. ex Gitmez, 1970 Phoberocysta neocomica Prolixosphaeridiumy sp. A cf. Pterospermopsis sp. Sentusidinium^ sp. A Tapeinosphaeridium pericompsum Wallodinium krutzschi L’association est dominee au point de vue quantitatif par les especes Druggidium apicopaucicum et Occisucysta sp. ex Gitmez 1970; Clvytroeisphaeridia clvytroeides, Gonyaulaeysta cf. diutina, Tapeinosphaeri- dium pericompsum, Cometodinium^ sp., Prolixosphaeridium? sp. A, Dino- flagelle type A, sont communes. Druggidium apicopaucicum, Occisucysta sp. ex Gitmez 1970, Phoberocysta neocomica et Gonyaulaeysta cf. diutina sont les especes les plus significatives de ce niveau. Druggidium apicopaucicum est l’espece index de la zone palynologique connue sous ce nom de l’intervalle du Berriasien terminal et du Valanginien inferieur (parțial phylozone) de l’Atlantique ă Cape Hatteras et aux Bahamas (H a b i b, 1975); la dis- tribution stratigraphique de cette espece serait, selon cet auteur, du Berriasien au Barremien. Occisucysta sp. ex Gitmez, 1970 (trouvee par Gitmez dans le Kimmâridgien Clay, 1970) est interessante tenant compte de la repartition stratigraphique du genre Occisucysta, qui s’etend du Kimmeridgien au Barremien; cette espece est aussi trăs proche de Diacanthum hollisteri H a b i b, 1972, espece cantonn^e dans le Berriasien de France (H a b i b & W a r r e n, 1973; cf. H a b i b, 1975) et du Berriasien-Valanginien de l’Atlantique du Nord (Habib, 1975). Phoberocysta neocomica, espece index de la zone (assemblage zone) du meme nom des formations de Missisauga et Verril Canyon(Berriasien- Valanginien), du Scoțian Shelf et des Grand Banks de l’Atlantique (W i 11 i a m s, 1975 ; B u j ak & Williams, 1978), et des formations du Berriasien-Valanginien de l’Atlantique au voisinage des cotes de l’Afri- que (Plateau marocain; Williams, 1978) a une distribution strati- graphique du Berriasien au Barremien (D a v e y & V e r d i e r, 1974 ; V e r d i e r, 1975). Phoberocysta neocomica a etd trouvee dans les coupes stratotypiques du Berriasien au Barremien; sa prâsence â la base de l’Aptien inferieur a Egalement ete signalee (M i 11 i o u d, 1969 ; Angles), quoique dans la section de La Bedoulle elle n’ait pas 6te trouvee (ă cause du facies, selon D a v e y & V e r d i e r, 1974); aussi sa presence dans l’Aptien est ineertaine. A 1 b e r t i (1961) signale cette espece dans le Neocomien d’Allemagne et de Pologne; Balteș (1971) reconnaît une zone avec Phoberocysta neocomica (Wetzeliella neocomica) dans le Berriasien-Hauterivien de la Plate-forme moesienne. Institutul Geological României 110 EM. ANTONESCU, E. AVRAM 14 Gonyaulacysta diutina a et4 decrite par Duxbury (1977) dans les argiles de Speeton, dans L’intervalle Berriasien-Hauterivien. Tenant compte de l’abondance de D. apicopaucicum et des simili- tudes qui existent entre la composition de l’association de ce niveau et celui de la zone â Druggidium apicopaucicum de l’Atlantique du Nord, il est â supposer que l’association du niveau 11021/7341 appartienne â la limite Berriasien-Valanginien ou â la base du Valanginien inferieur. Plus băut, dans les niveaux MO23/7951, MO24/7952, 11025/7953, la microflore est tres pauvre, et bon nombre d’exemplaires sont indeter- minables ; seulement D. apicopaucicum et Oceisueysta sp. ex G i t m e z, 1970 ont pu etre identific. Deux changements qualitatifs et quantitatifs se produisent dans un intervalle relativement râduit au point de vue de l’epaisseur strati- graphique, notamment celui des niveaux MO30/7493 et MO36/7494. L’association de dinoflagelles du niveau 11030/7493 comprend : Achomosphaera neptuni cf. Amphorula metaelliptica Cassiculosphaeridia magna Cometodinium^ sp. Dinoflagelle type A Dingodinium albertii Hystrichodinium voigti Gonyaulacysta sp. B Kleithriasphaeridium fascilatum Muderongia staurota Oceisueysta sp. ex G i t m e z, 1970 Oligosp haei'idium asterigium cf. Operculodinium sp. Phoberocysta neocomica Sentusidinium sp. A Sentusidinium sp. B Spiniferites ramosus Tapeinosphaeridium pericompsum Wallodinium hrutzschi cf. Xenieodinium densispinosum On observe qu’a ce niveau D. apicopaucicum a dispăru (il reappa- raîtra en faibles pourcentages plus băut), mais Oceisueysta, persiste. Trois especes disparaissent definitivement (Gonyaulacysta sp. A, Prolixosphae- ridium^ sp. A. et Muderongia cf. tomaszowensis). Deux especes font leur apparition en abondance, Kleithriasphaeridium fasciatum (distribution stratigraphique connue du Berriasien au Barremien; Duxbury, 1977) et Oligosphaeridium asterigium, espece censâe faire son debut au Valan- ginien inferieur et qui a ete trouvee jusqu’au Barremien (D u x b u r y, 1977). Ensemble avec ces especes, mais tres rare (un exemplaire) apparaît Dingodinium albertii (sensu D u x b u r y, 1977), avec une distribution stratigrapbique allant du Titbonien â l’Albien (selon Duxbur y, 1977 et Davey &Verdier, 1974; Dingodinium cf. albertii citâ par Institutul Geological României 15 dinoflagellEs du cretace inferieur de svinița 111 loannides, SHvrinos&Do wnie, 1976, du Kimmeridgien d’Angle.terre est different). Dingodinium albertii devient tres abondant â partir du Barremien superieur jusqu’â l’Albien inferieur dans la formation de Svinița. Achomosplwera neptuni, dont l’extension stratigraphique est censee d’etre le Berriasien-Aptien (selon D u x b u r y, 1977) ou Berria- sien-Valanginien (selon Williams, 1978), fait aussi son apparition ă ce niveau. Cassiculosphaeridia magna (Berriasien-Barr6mien, selon Duxbury, 1977) apparaît dans ce niveau ensemble avec les sous- especes de Spiniferites ramosus qui selon Har k e r & S a r j ea n t (1975) font leur dâbut au Valanginien. Une espece fort interessante, cf. Ampho- rula metaelliptica, ayant une extension stratigraphique limit^e au Titho- nique-Berriasien (H a b i b, 1975) a et6 ddcrite d’abord au Tithonique de Bulgarie (D o d e k o v a, 1969) et retrouv6e dans le Berriasien de l’Atlantique de l’Ouest et dans celui du stratotype de Berrias (H a b i b, 1972, 1975); cette espece est presente dans la formation de Murguceva seulement ă ce niveau. Nous devons sp6cifier igi que de tres nombreux exemplaires de Amphorula metaelliptica ont 6te trouvâs par l’un de nous (E. A n t o n e s c u) dans une formation de Dobrogea ayant des simi- litudes de palynofacies avec le Purbeekien; les exemplaires sont conformes â ceux decrits par Dodekova (1969). Les exemplaires de Murgu- ceva sont seulement conferes ă ce genre et espece. Dans le niveau MO36/7494 l’association de dinoflagell6s est la suivante: Achomosphaera neptuni Biorbifera johnewingi Biorbifera sp. A Cleistosphaeridium sp. A Chytroeisphaeridia chytroeides Cometodiniuml sp. Cyclonephelium distinctum Dinoflagelle type A Dingodinium albertii Druggidium apicopaucicum Gonyaulacysta cf. diutina Occisucysta sp. ex G i t m e z, 1970 Occisucysta tentoria cf. Operculodinium sp. Phoberocysta neocomica Polysphaeridium warreni Polysphaeridium cf. laminaspinosum Pseudoceratium pelliferum Spiniferites ramosus Tapeinosphaeridium pericompsum Tanyosphaeridium sp. A Wallodinium krutzschi cf. Xenicodinium densispinosum nstitutul Geological României 112 EM. ANTONESCU, E. AVRAM 16 Par rapport au niveau precedent, il faut noter la reapparition de D. apicopaucicum en faibles pourcentages et la pr&ence de quelques es- peces tres significatives. P. pelliferum, decrite d’abord en Allemagne par Go eh t (1957)) a une distribution stratigraphique du Berriasien au Barremien (Duxbury, 1977; Williams, 1978); elle apparaît â ce niveau et sera une presence constante, en pourcentages reduits, dans les formations de Murguceva et Svinița. Biorbifera johnewingi est une espece tres caract6ristique ayant, d’apres les donnâes connues jusqu’ă present, une distribution stratigra- phqiue restreinte au Berriasien-Valanginien moyen (H a b i b & W a r- r e n, 1973 ; cf. Habib, 1975), avec une râpartition geographique large, quoique etant generalement peu abondante (P o c o c k, 1976). Bior- bifera johnewingi est l’espece index d’une zone palynologique definie au Canada arctique (Deer Bay Formation) dans les niveaux contenant Thorsteinssonoceras ellesmerensis, Buchia keyserlingi, Polyptychites key- serlingi et Tollia mutabilis, correspondant aux zones ă Killianella rou- baudiana et â Baynoceras verrucosum, donc au Valanginien inferieur et moyen (P o c o c k, 1976). Dans l’Atlantique du Nord-Ouest, (Cape Hatteras et aux Bahamas), Biorbifera johnewingi est le fossile index d’une zone palynologique correspondant â l’intervalle Berriasien, limite Berria- sien-Valanginien, et allant jusqu’au Valanginien (Habi b, 1975); dans le Scoțian Shelf et les Grand Banks de l’Atlantique du Nord (formations de Mississauga et Verril Canyon) elle est pr&ente dans le Berriasien- Valanginien, respectivement dans la zone ă Phoberocysta neocomica (W i 1- 1 i a m s, 1975; Bujak& Williams, 1978). Biorbifera johnewingi a ete aussi rapporte du Berriasien de Californie (W a r r e n, 1967; selon H a b i b, 1975) et du Berriasien de Berrias par H a b i b & W a r- r en (1973); cf. H a b i b, 1975) et « in thebasal Cretaceous typesections of Europe» par Millioud (1975; cf. Habib, 1975). Sa presence dans le niveau MO36/7494 pourrait-elle indiquer que ce niveau appar- tient encore au Valanginien moyen ou que cette espece est encore pre- sente au Valanginien superieur ? II faut aussi noter la presence dans le meme niveau d’une autre espece de Biorbifera, Biorbifera sp. A. Polysphaeridium warreni, espece tres abondante au niveau 51036/ /7494, a une distribution stratigraphique du «Portlandien » au Barre- mien (H a b i b & W a r r e n, 1973 ; cf. Habib, 1975) et est presente dans l’Atlantique du Nord-Ouest (Cape Hatteras et Bahamas), du Ber- riasien au Barremien (Habi b, 1975), dans le Berriasien de Californie (W a r r e n, 1967 ; selon Habib, 1975), dans le Berriasien de Berrias (H a b i b & W a r r e n, 1973 ; of. Habib, 1975) et dans l’Atlantique de l’Est au voisinage des câtes d’Afrique, preș du Senegal, dans le Port- landien (sous le nom de Bystrichosphaeridium’l sp. A ; Habib, 1972; Williams, 1978). Dans le niveau MO36/7494 il y a aussi beaucoup d’exemplaires qui sont plus proches de P. laminaspinosum; Cyclonephe- lium distinctum, Occisucysta tentoria, Achomosphaera neptuni, Bccisueysta, sp. ex G i t m e z, 1970, y font leur apparition ou sont encore presentes dans ce niveau. y Institutul Geological României \ 16 r/ 17 DINOFLAGELLES du cretace inferieur de svinița 113 Tenant compte de ces donnees, l’intervalle marqu6 par les niveaux MO30/7493 et MO36/7494 confirme I’âge valanginien attribue â ces depots grâce aux ammonites. Au niveau MO41/7495 il y a un nouveau changement dans l’asso- ciation de dinoflagellds qui comporte les especes : Apteodinium cf. conjunctum Baltisphaeridium sp. B ex H a b i b, 1971 Cassiculosphaeridia magna Cribroperidinium orthoceras cf. Ctenidodinium elegantulum Cyclonephelium distinctum Dinoflagell6 type A Dingodinium albertii Druggidium apicopaucicum Druggidium deflandrei Gonyaulacysta sp. B Meiourogonyaulax stoveri Phoberocysta neocomica Pseudoeeralium. pelliferum Oligosphaeridium complex Oligosphaeridium cf. diastema cf. Operculodinium sp. Sentusidinium sp. B Tapeinosphaeridium cf. granulatum Wallodinium krutzschi On observe (pl. I) que l’association a beaucoup changd par rapport â celle des niveaux MO30/7493-MO36/7494. Druggidium apicopaucicum a presque completement dispăru (1 exem- plaire) et ă sa place apparaît une autre espece Druggidium deflandrei. Les especes les plus significatives des niveaux inferieurs, Occisucysta sp. ex G i t m e z, 1970, Gonyaulacysta cf. diutina, Biorbifera johnewingi, Polysphaeridium warreni, Achomosphaera neptuni cf., Amphorula metael- liptica, Oligosphaeridium asterigium, Kleithriasphaeridium fasciatum dis- paraissent. Parmi les especes qui y persistent, Dingodinium albertii est reprdsentde par des exemplaires plus nombreux et Cyclonephelium dis- tinctum devient plus abondante; Oligosphaeridium complex y est abon- dante, ainsi que deux especes attribuees provisoirement au genre Sentu- sidinium — Sentusidinium sp. B, Sentusidinium sp. C. Cribroperidinium orthoceras, Oligosphaeridium cf. diastema, Tapeinosphaeridium cf. granulo- sum, font leur apparition â. ce niveau des calcaires siliceux, ainsi que Meiourogonyaulax stoveri et cf. Ctenidodinium elegantulum. Druggidium deflandrei (distribution stratigraphique Valanginien- Barremien cf. Hab i b, 1975) est l’espece index d’une phylozone d’âge valanginien-hauterivien ou hauterivien dans l’Atlantique du Nord-Ouest (Cape Hatteras et Bahamas). Oligosphaeridium complex (espece^ qui fait son debut dans le Valanginien de Berrias et est presente aussi â la base de l’Hauterivien du stratotype — M i 11 i o u d, 1969) est l’espece index 8 — c. 658 Institutul Geologic al României L iGRy 114 EM. ANTONESCU, E. AVRAM 18 d’une concurrent-range zone, qui va du « Valanginien ou de l’Hauterivien au Barremien (ou â l’Aptien?) », identifiee dans le Neocomien de l’Atlan- tique du Nord (H a b i b, 1975). Ctenidodinium elegantulum, ayant une distribution stratigraphique du Valanginien au Barremien (D u x b u r y, 1977), est l’espece index d’une assemblage-zone d’âge hauterivien recon- nue dans les formations de Mississauga et Verril Canyon des Grand Banks et du Scoțian Shelf de l’Atlantique du Nord et dans l’Hauterivien de l’A- tlantique de l’Est, preș des cotes de l’Afrique — plateau marocain (W i 1- liams, 1975; B u j a k & W i 11 i a m s, 1978). Meiourogonyaulax sto- veri, espece ayant une distribution stratigraphique du Valanginien ă l’Aptien, fait aussi son apparition â ce niveau et devient tres abondante ă partir du Barremien inferieur dans la formation de Svinița. Oligosphae- ridium complex, Cyclonephelium distinctum, Sentusidinium sp. B sont au point de vue quantitatif les constituants principaux de l’association. Tenant compte seulement de la rdpartition stratigraphique des especes dece niveau, il est difficiled’enpreciser l’âge, parce que l’intervalle de distribution de la plupart des elements constituants va du Berriasien ou du Valanginien jusqu’au Barrdmien. Des especes dont le debut est dans l’Hauterivien manquent. Aussi la limite avec l’Hauterivien pourrait etre tracee entre ce niveau et le niveau sous-jacent seulement â cause de la disparition des especes valanginiennes, â cause du renouvellement de l’association de dinoflagelles et parce que cette association est similaire â celle de la coupe du Pîrîul Morilor, qui comporte en outre Spiniferites dentatus, espece qui fait son debut dans l’Hauterivien. C. Distribution de dinoflagelles dans Ia formation de Svinița Coupe de Pîrîul Morilor Nous allons examiner la coupe de Pîrîul Morilor (pl. II) seulement â partir des niveaux calcaires â accidents siliceux ou nous avons trouve des dinoflagellds. A partir des niveaux VI = 8/7496 , ă onze ou douze metres au-dessus de la limite des calcaires â accidents siliceux avec les calcaires detritiques et jusqu’au niveau V7/2 = 13/7501, l’association est du meme type: Apteodinium conjunctum Baltisphaeridium sp. B ex H a b i b, 1971 Batioladinium sp. Broomea^ sp. Cassiculosphaeridia magna Cribroperidinium orthoceras Cleistosphaeridium ? sp. A ■ cf. Ctenidodinium elegantulum Dinoflagelle type A Dingodinium albertii Druggidium deflandrei Gonyaulacysta cf. diutina Gonyaulacysta sp. B 19 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 115 cf. Leptodinium sp. cf. Millioudodinium sp. Muderongia cf. mcwhaei Muderongia staurota Muderongia cf. tomaszowensis cf. Cyclonephelium hystrix CycloneplieUum distinctum Meiourogonyaulax stoveri cf. Operculodinium sp. Oligosphaeridium complex Oligosphaeridium cf. diastema Phoberoeysta neocomica Pseudoceratium pelliferum Sentusidinium sp. B Sentusidinium ? sp. C cf. Sentusidinium ? atlanticum Spiniferites dentatus Spiniferites ramosus Systematophora complicata Tapeinosphaeridium cf. gramdatum Wallodinium krutzschi Cette association est pareille â celle rencontree â la pârtie supe- rieure de la coupe de Murguceva au niveau MO41/7495. Une espece int6- ressante pour cet intervalle est Spiniferites dentatus, ddcrite de l’Hauteri- vien d’Allemagne (Goeht, 1957) et identifice depuis l’Hauterivien jus- qu’au Barremien dans les argiles de Speeton par Duxbury (1977), ainsi que dans l’Hauterivien de l’Atlantique du Nord — Scoțian Shelf et de l’Atlantique de l’Est, preș des cotes de l’Afrique — Sânegal (B u j a k & W i 11 i a m s, 1978). La repartition de chaque espece dans les diffe- rents niveaux est represent6e dans la planche II. La proportion des ele- ments predominants est la meme (l’association est caracterisee par la pr6- dominance P Oligosphaeridium complex, Cyclonephelium distinctum, Sen- tusidinium sp. B, Sentusidinium1! sp.C) qu’au niveau MO41/7495 de la coupe de Murguceva; les associations de dinoflagelles des niveaux men- tionnes dans les coupes de Murguceva et de Pîrîul Morilor sont donc du meme âge, qui doit etre l’Hauterivien, tenant compte de la presence de l’espece Spiniferites dentatus qui debute â l’Hauterivien et du fait que cette association est situde entre une association valanginienne et une associa- tion du Barremien inferieur. A partir du niveau V7/2 = 13/7501, un nouveau changement se produit dans l’association de dinoflagelles. L’association est presque la meme que celle de l’intervalle marque par les niveaux VI = 8/7496 — — V6 = 12/7500 (seule Odontochitina operculata fait son apparition), mais la proportion des Elements constituants est toute autre. Dingodinium albertii, Meiourogonyaulax stoveri, les especes du groupe Spiniferites ra- mosus, Gonyaulacysta sp. B, et une espece d’acritarche Baltisphaeridium sp. B ex Singh, 1971 deviennent fort abondantes. Des especes qui 116 EM. ANTONESCU, E. AVRAM 20 formaient le fond de l’association hauterivienne, seule Cyclonephelium distinctum reste abondante; les deux especes de Sentusidinium (C et B) sont plus faiblement representees, ainsi que Oligosphaeridium complex. Ce type d’association est observable jusqu’au niveau V8/1 = 14/7502. Cette association appartient au Barremien selon les ammonites (Barremien inferieur, zones ă Paraspiticeras et Pseudothurmannia et zone ă Leptoceras et Holcodiscus), l’abondance en Dingodinium albertii — es- pece tres proclie de D. cerviculum Cookson&Eisenack, 1958, tres frequente dans le Barremien de la Dobrogea et de la Plate-forme moesienne (B a 11 e ș, 1971 et 1974) etant aussi un argument dans ce sens. A pârtii' du niveau V8/5 = 15/7504, un nouveau changement se produit dans l’association de dinoflagelies par l’apparition de l’espece Prolixosphaeridium parvispinum, espece qui fait son debut ă la pârtie terminale du Barremien inferieur, respectivement au Barremien «moyen » sensu D a v e y & V e r d i e r (1974), quoique d’autres auteurs la trau- vent au Jurassique?. Cette espece, identique ă Prolixosphaeridium dei- rense D a v e y, Do wnie, Sarjeant&Willi ams, 1966 et consi- der6e synonyme de P. parvispinum par Davey&Verdier (1974) est probablement un bon marqueur â Svinița au moment de son appa- rition du Barremien superieur. Nous considerons donc que, conf or moment ă la distribution des ■dinoflagelies, c’est au niveau V8/5 = 15/7504 que commence le Barre- mien superieur. L’association du niveau V8/5 = 15/7504 se maintient avec les memes caracteres jusqu’ă la pârtie superieure de la coupe du Pîrîul .Morilor Vll/2 = 19/7507. Elle comprend : Batioladinium sp. Baltisphaeridium sp. B. ex Singh, 1971 Cribroperidinium orthoceras Coronifera oceanica Cometodinium ? sp. Cymatiosphaera paclvytheca Dingodinium albertii Druggidium deftandrei Gonyaulaeysta sp. B Gonyaulaeysta sp. C Cyclonephelium distinctum cf. Leptodinium sp. Meiourogonyaulax stoveri Muderongia mcwhaei Oligosphaeridium cf. diastema Oligosphaeridium complex Odontochitina operculata Prolixosphaeridium parvispinum Pseudoceratium pelliferum Pterospermopsis spp. (voir chapitre III. A) Sentusidinium^ sp. C Sentusidinium sp. B Institutul Geologic al României XJGRy 21 dinoflagelles du cretace inferieur de svinița 117 Sentusidinium^ sp. D Subtilisphaera cf. perlucida Spiniferites ramosus Tanyosphaeridium sp. B Wallodinium krutzschi L'apparition de quelques especes nouvelles ă la pârtie supe- rieure de la succession stratigraphique de la coupe de Pîrîul Morilor semble presenter â la premiere vue un interet ehronostratigraphique. Mais les especes de Pterospermospsis et Cymatiosphaera pachytheca sont liees plutot aux conditions locales de facies marquees au Barremien superieur par un enrichissement progressif en spores et pollens trahissant la proxi- mite d’une aire continentale. Ce palynofacies avec Cymatiosphaera, Ptero- spermopsis et nombreux spores et pollens semble etre lie aux mouvements de surrection qui ont culmine sur le territoire des Carpathes de Rou- manie ă l’Aptien. Subtilisphaera cf. perlucida est cite comme debutant au Valangi- nien des diverses regions du monde par H a r k e r & S a r j e a n t (1975), donc son apparition â la pârtie superieure de la coupe n’a probablement qu’une signification ecologique. S. perlucida a ete rencontre dans beau- coup de regions du monde dans le Cretace inferieur, dans l’Hauterivien du stratotype (M i 11 i o u d, 1969), dans l’Atlantique du Nord (Scoțian Shelf et Grand Banks) de l’H a u t er i v i e n â l’Aptien (B u j a k& & W i 11 i a m s, 1978), en Angleterre (Speeton Clay) dans le Barremien superieur' (D a v e y, 1974) etc. Coupes de Pîrîul Țiganilor, Temeneacia, route Orșova-Svinița, port de Svinița Les echantillons qui proviennent de la pârtie superieure de la for- mation de Svinița (sous-formation de Temeneacia) et qui ont ete prelevâs des coupes Pîrîul Țiganilor, Temeneacia, la route Orșova-Svinița (pl. III) contiennent le meme type d’associations que plus haut: Cleistosphaeridium^ sp. A Cribroperidinium orthoceras Cometodinium ? sp. Cyclonephelium distinctum Dinoflagelle type A Dingodinium albertii Druggidium deflandrei Florentinia mantelli Fromea amphora Gonyaulacysta sp. A Gonyaulacysta sp. B Meiourogonyaulax stoveri Odontochitina operculata Oligosphaeridium complex Prolixosphaeridium parvispinum Pterospermopsis spp. Institutul Geological României 118 EM. ANTONESCU, E. AVRAM 22 Sentusidinium ? sp. D Spiniferites ramosus Tapeinosphaeridium cf. granulatum cf. Silicisphaera sp. Wallodinium lerutzschi L’association de dinoflagelles troiivde dans ces coupes (pl. III) est semblable â celle de Ia pârtie supdrieure de Ia formation de Svinița de la coupe de Pîrîul Morilor entre les niveaux V8/5 = 15/7504 — Vll/2 = = 19/7507 ; en plus, ici apparaissent Florentinia mantelli, espece qui de- bute dans le Barr6mien selon D a v e y & V e r d i e r (1976) et des exem- plaires attribuds avec doute au genre Silicisphaera. Cette association ap- partient au Barrdmien superieur et ă l’Aptien inferieur selon les ammo- nites. II est â remarquer que l’association de dinoflagelles ne subit pas de modifications notables, ni â la limite Barrdmien-Aptien, ni dans l’in- tervalle de l’Aptien inferieur; c’est la meme association de dinoflagelles. IV. CORRELATION ENTRE ASSOCIATIONS DE DINOFLAGELLES ET ZONES D AM- MONITES ET DE CALPIONELLES DU CRETACE INFERIEUR DE SVINIȚA. CORRE- LATIONS INTERREGIONALES. Ainsi qu’il resulte du chapitre precedent, dans les formations de Murguceva et Svinița une distribution stratigraphique zonaire des dino- flagelles â ete observee. Nous allons presenter ces zones, qui sont des bio- zones avec une valeur que nous considerons pour le moment locale. L’âge de ces zones est etabli suivant la corrdlation avec les zones de calpionelles et d’ammonites. Les zones de dinoflagelles du Cretace inferieur de Svinița ont beaucoup de traits communs avec les zones palynologiques dtablies dans le Cr6tac6 inferieur d’autres r^gions du monde; des correlations peu- vent etre faites entre ces zones. Zone ă Druggidium apicopaucicum et Phoberocysta neocomica $ • (Concurrent range — zone) Biozone mise en evidence dans le ruisseau de Murguceva (pl. I) dans l’intervalle compris entre environ 28 metres et environ 60 metres au-dessus de la base de la formation du Murguceva, c’est-ă-dire dans l’intervalle MO21/7341 et MO38 ou 39 (au-dessus de MO36/7494 et au- dessous de MO41/7495). L’intervalle stratigraphique dans lequel cette zone a ete mise en evidence est-il d’environ 35 metres ? Les especes index font leur d^but â partir du Berriasien. D’autres especes pr^sentes dans cette biozone sont: Gonyaulacysta sp. A, Cometo- dinium^ sp., Gonyaulacysta cf. diutina, Occisucysta sp. ex G i t m e z, 1970, Wallodinium lerutzschi, cf. Pterospermopsis sp., Prolixosphaeridium sp. A, Muderongia cf. tomaszowensis, Sentusidinium 1 sp. A, Muderongia staurota, Kleithriasphaeridiurn fasciatum, Cassiculosphaeridia magna, Acho- mosphaera neptuni, Gonyaulacysta sp. B, Oligosphaeridium asterigium, les sous-especes du groupe Spiniferites ramosus, Sentusidinium sp. B, Pseudo- Institutul Geological României 23 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 119 ceratium pelliferum, Polysphaeridium warreni, Cyclonephelium distinctum, Tanyosphaeridium sp. A, Occisucysta tentoria. Des especes dont la distribution stratigraphique est connue comme debutant au Jurassique superieur ou au Berriasien inf6rieur, mais qui s’eteigncnt dans cette zone, sont : Chytroeisphaeridia chytroeides, Occi- sucysta sp. ex Gi t mez, 1970, cf. Xenicodinium densispinosum, Tapei- nosphaeridium pericompsum, cf. Amphorula metaelliptica, Biorbifera johnewingi. La zone â Druggidium apicopaucicum et Phoberocysta neocomica ■correspond â la pârtie terminale de la zone Calpionellopsis, la zone Cal- pionellites et aux niveaux qui comportent Kilianella ex gr. roubaudiana et Olcostephanus spp. L’âge de la zone â Druggidium apicopaucicum et Phoberocysta neocomica correspond a l’intervalle Berriasien superieur- Valanginien. On peut correler le contenu en dinoflagelles de cette biozone avec le contenu en dinoflagelles du Berriasien et du Valanginien des strato- types (M i 11 i o u d, 1969 ; H a b i b & W a r r e n, 1973 cf. Ha b i b, 1975 ; M i 11 i o u d, 1975 cf. H a b i b, 1975), avec la zone â Druggi- dium apicopaucicum, (Berriasien-Valanginien) du Neocomien de l’Atlan- tique du Nord — 600 km Est du Cape Hatteras et du Blake Bahamas Outer Eidge System (DSDP site 50 et DSDP sites 99, 100,101; H a b i b, 1975), avec la zone â Phoberocysta neocomica des formations Mississauga et Verril Canyon du Scoțian Shelf et Grand Banks de l’Atlantique cana- dien (Williams, 1975; Bujak& Williams, 1978), avec la zone â Phoberocysta neocomica de l’Atlantique de l’Est preș des cotes de l’Afrique au Nord-Ouest du plateau marroeain (Williams, 1978) et partiellement avec la zone ă Phoberocysta neocomica trouvee par Balteș (1971) dans la Plate-forme moesienne. La distribution stratigraphique des genres et especes dans cette zone suggere la possibilit6 de la diviser en deux sous-zones, une infârieure, ă Druggidium apicopaucicum, et l’autre, sup^rieure, avec Oligosphaeridium asterigium, Polysphaeridium warreni et Biorbifera johmewingi. Des recher- ches ult&’ieures pourront prouver que ces sous-zones representent en lAa- litâ deux zones distinctes, mais pour le moment, â cause de la distribu- tion stratigraphique — on voit que plusieurs especes significatives font leur apparition dans des niveaux diff^rents — ou elles sont tres rares, par exemple Biorbifera johnewingi, ou elles sont abondantes mais canton- nees seulement dans un seul niveau, par exemple Oligosphaeridium as- terigium. Ainsi nous consid6rons ces deux associations comme repr^sen- tant les sous-zones d’une seule biozone ă Phoberocysta neocomica et Drug- gidium apicopaucicum. La sous-zone â Druggidium apicopaucicum ne se piAsente bien de- finie que dans le niveau MO21/7341 (pl. I) de la coupe du ruisseau Murgu- ceva; les associations des niveaux MO23/7951, MO24/7952, MO25/7953 lui appartiennent probablement aussi. L’intervalle stratigraphique qui revient ă cette sous-zone est d’en- viron 10 metres? IGR/ Institutul Geological României 120 EM. ANTONESCU, E. AVRAM 24 Cette sous-zone est caracterisee par l’abondance en Druggidium apicopaucicum (donc elle est partiellement une zone d’acmde) et par la prâsence K Occisucysta sp. ex Gitmez, 1970. Les especes qui font leur dâbut dans cette sous-zone sont : Gonyaulacysta sp. A, Gonyaulacysta cf. diutina, Cometodinium^ sp., Wallodinium krutzschi, cf. Pterospermopsis sp., Prolixosphaeridium sp. A, Muderongia cf. tomaszowensis, Sentusidi- nium ? sp. A. La sous-zone ă Druggidium apicopaucicum correspond â la pârtie terminale de la zone Calpionellopsis et â la pârtie infCrieure de la zone Calpionellites ; l’âge de cette sous-zone est donc equivalent du Berriasien superieur et du Valanginien inferieur. La sous-zone ă Oligosphaeridium asterigium, Polysphaeridium war- reni et Biorbifera johnewingi correspond â l’intervalle marquCparles ni- veaux MO30/7493 — MO36/7494 de la coupe du ruisseau Murguceva. L’intervalle stratigraphique qui revient ă cette sous-zone est d’en- viron 20 metres. Elle est caracterisee par la presence des especes Oligosphaeridium asterigium, Polysphaeridium warreni et Biorbifera johnewingi. C’est dans le meme intervalle que debutent aussi : Muderongia staurota, Kleithrias- phaeridium fasciatum, Cassiculosphaeridia magna, Achomosphaera neptuni, Gonyaulacysta sp. B, les sous-especes du groupe Spiniferites ramosus, Sentusidinium sp. B, Pseudoceratium pelliferum, Cyclonephelium distinc- tum, Tapeinosphaeridium sp. A, Occisucysta tentoria. Les especes qui font leur apparition au Jurassique ou au Berria- sien, mais qui s’eteignent dans cette sous-zone, sont : Chytroeisphaeridia chytroeides, Occisucysta sp. ex G i t m ez, 1970, cf. Xenicodinium densi- spinosum, Tapeinosphaeridium pericompsum, cf. Amphorula metaellip- tica, Biorbifera johnewingi. En outre y sont presents Dingodinium albertii (tres rare), Tanyosphaeridium sp. A, Biorbifera sp. A. La sous-zone â Oligosphaeridium asterigium, Polysphaeridium war- reni et Biorbifera johnewingi est equivalente de la zone Calpionellites et de l’intervalle stratigraphique dans lequel ont ete trouvCes Kilianella ex gr. roubaudiana { = Valanginien inferieur ) et Olcostephanus sp. (= Va- langinien superieur1 â la limite avec l’Hauterivien). L’âge de cette sous-zone correspond au Valanginien. Les dinoflagelles de la sous-zone â Oligosphaeridium asterigium, Polysphaeridium warreni et Biorbifera johnewingi peuvent etre correles avec ceux de la zone ă Biorbifera johnewingi de la Deer Bay Formation du Canada de l’Ouest, trouvCe dans les depots avec Thorsteinssonoceras ellesmerensis et Buchia keyserlingi ( = la zone â Kilianella roubaudiana) et les depots â Polyptychites keyserlingi, Tollia mutabilis et Buchia paci- fica ( = la zone â Saynoceras vemicosum identifice par P o c o c k (1976). Zone â Oligosphaeridium complex et Druggidium deflandrei (Con- current range-zone) Cette biozone a ete identific ă la pârtie supCrieure des calcaires â accidenta siliceux de la coupe de Murguceva, ă partir du niveau MO41/ Institutul Geological României (GR 7 25 DINOFLAGELLES du cretace inferieur de svinița 121 /7495 situ6 au-dessus de la base de ces calcaires et dans la coupe du Pîrîul Morilor â la pârtie superieure des calcaires a accidents siliceux (formation de Murgueeva) et ă la base des calcaires marneux et schisteux de la for- mation de Svinița (sous-formation de Pîrîul Morilor), c’est-ă-dire 10—15 metres au-dessus de la limite des calcaires siliceux avec les calcaires d6- tritiques (niveau Vl/8 = 7496) et jusqu’â environ 48 metres au-dessus de cette limite (niveau V6 = 12/7500, voir planche II). L’intervalle strat’graphique qui revient â cette biozone est epais d’environ 25 metres dans la coupe de Murgueeva et d’environ 48 metres dans la coupe de Pîrîul Morilor. Cette zone est caract6risde par l’apparition des especes Oligosphaeri- dium complex (debut Valanginien-Hauterivien) et Druggidium deflandrei (Valanginien-Barremien). Y font aussi leur apparition : Sentusidinium 1 sp. C, Cribroperidinium orthoceras, Ctenidodinium elegantulum, Apteo- dinium conjunctum, Baltisphaeridium sp. B ex Habib, 1971, Oligo- sphaeridium cf. diastema, Tapeinosphaeridium cf. granulosum, Meiouro- gonyaulax stoveri, Broomea^ sp., Spiniferites dentatus, cf. Sentusidinium? atlanticum, Batioladinium sp. Les especes qui disparaissent dans cette zone sont : Druggidium apicopaudcum, Oligosphaeridium asterigium, Klei- thriasphaeridium fasciatum, Ctenidodinium elegantulum, Apteodinium con- junctum, et les especes qui la transgressent sont : Gonyaulacysta cf. diu- tina, Muderongia cf. tomaszowensis, Muderongia staurota, Pseudoceratium- pelliferum, Phoberocysta neocomica, Cassiculosphaeridia magna, Wallo- dinium Icrutzschi, Dingodinium albertii, Dinoflagell6 type A, Gonyaula- cysta sp. B, les sous-especes du groupe Spiniferites ramosus, Cyclonephe- lium, distinctum, Cometodiniuml sp. Cette zone est caraeterisee aussi par l’abondance des especes Oligo- sphaeridium complex, Cyclonephelium distinctum, Sentusidinium9: sp. C, Sentusidinium sp. B et partiellement (seulement dans la coupe de Pîrîul Morilor) par la presence de Spiniferites dentatus, espece qui fait son debut â l’Hauterivien. La biozone â Oligosphaeridium complex et Druggidium deflandrei commence dans la coupe de Murgueeva au-dessous du niveau â Tesche- nites pachydicranus, â la limite Valanginien-Hauterivien, et est corrdlable sur la coupe du ruisseau Morilor avec l’intervalle contenant Spitidiscus cf. incertus, Crioceratites majoricensis, Crioceratites matsumotoi et la biozone â Acrioceras seringei et Paraspiniceras jourdani. L’âge de cette zone iden- tifice â la pârtie superieure de la formation de Murgueeva et â la pârtie inferieure de la formation de Svinița est l’Hauterivien. On peut corrdler cette zone partiellement avec la zone â Oligosphae- ridium complex (d’âge valanginien-barrdmien) du Neocomien de l’Atlan- tique du Nord (H a b i b, 1975), avec la zone â Ctenidodinium elegan- tulum de l’Hauterivien de l’Atlantique de l’Est — DSDP 370 preș de la bordure du plăteau marocain — les cotes de l’Afrique, pai’ la presence de Spiniferites dentatus, Oligosphaeridium complex, Ctenidodinium elegan- tulum-, avec l’Hauterivien d’Allemagne (Goeht, 1957; 1959) et celui A Institutul Geologic al României iGRy 122 ANTONESCU, E. AVRAM 2& des stratotypes du Cretace inferieur par la composition generale de l’asso- ciation. Zone « Dingodinium albertii et Meiourogonyaulax stoveri (Peak-zone ) Cette biozone a identifice seuiement dans la coupe de Pîrîul Morilor dans l’intervalle compris entre environ 16 et 33 metres au-dessus- de la limite entre les calcaires â accidents siliceux et les calcaires mar- neux de la formation de Svinița (sous-formation de Pîrîul Morilor), c’est- ă-dire dans l’intervalle qui comprend les niveaux V7/3 = 13/7501 iu V8/5- = 15/7504 (un peu au-dessous de ce dernier niveau, voir la planche II). L’intervalle stratigraphique qui correspond â cette biozone est Cpais d’environ 19 metres. Cette biozone est caracterisee par la predominance quantitative des especes Dingodinium albertii et Meiourogonyaulax stoveri, qu’on trouve dans les zones sous-jacentes en tres faibles pourcentages mais qui devien- nent brusquement abondantes dans cet intervalle. Dans cette biozone, Odontochitina operculata fait son apparition. Sentusidinium sp. B, Oligosphaeridium complex et Sentusidinium ! sp. C deviennent rares, tandis que Gonyaulacysta sp. B, les sous-especes du groupe Spiniferites ramosus, Baltisphaeridium sp. B ex H a b i b, 1971 croissent en abondance. Cyclonephelium distinctum s’y maintient abondante. Cette zone correspond aux biozones â Paraspiticeras et Pseudo- thurmannia et celle ă Leptoceras et Holcodiscus. Son âge est Cquivalent du Barremien inferieur. On peut corrâler cette zone, partiellement, avec la zone ă Dingo- dinium cerviculum et Apteodinium granulatum du Barremien de la Plate- forme moesienne (B a 11 e ș, 1971). Zone ă Prolixosphaeridium parvispinum (Concurrent range-zone) Cette biozone a Ctd mise en evidence dans les coupes de Pîrîul Mori- lor, Temeneacia, Pîrîul Țiganilor, de la route Svinița-Orșova, et du de- barcadere de Svinița, dans la formation de Svinița, notamment â la pârtie supCrieure de la sous-formation de Pîrîul Morilor et dans la sous-formation de Temeneacia (calcaires marneux, marnes, marnoargiles, planches II et III). L’intervalle stratigraphique qui revient â cette zone est epais d’en- viron 65 metres dans la coupe de Pîrîul Morilor et de 50 metres dans les coupes de Pîrîul Țiganilor completees par celle de Temeneacia (voir plan- ches II et III). Cette zone est caracterisee par l’apparition de l’espece Prolixos- phaeridium parvispinum, espece dont le debut est censC etre la pârtie terminale du Barremien inferieur, respectivement dans le «Barremien moyen » (D a v e y & V e r d i e r, 1974). Dans la region de Svinița le dCbut de cette espece se situe au niveau V8/5 = 15/7504, e’est-â-dire ă, la pârtie basale du Barremien supCrieur. Institutul Geological României 27 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 123 La biozone ă Prolixosphaeridium parvispinum correspond dans la coupe de Pîrîul Morilor ă l’intervalle qui comprend le sommet de la bio- zone ă Leptoceras et Dolcodiscus jusqu’ă la biozone ă Imerites et Eristavia y compris. Sur les coupes dePîrîul Țiganilor, Temeneacia, route Svinița- Orșova et le debarcadere de Svinița, la zone ă Prolixosphaeridium parvi- spinum correspond aux biozones ă Imerites et Eristavia, ă la biozone ă « Crioceratites » ex gr. barremense-wblgnyi et ă la biozone ă Pseudohaplo- ceras matheroni et Deshayesites weissi. L’âge de cette biozone correspond au Barremien superieur-Aptien inferieur. Le contenu en dinoflagelies de cette biozone peut etre corr616 avec le Barremien superieur des argiles de Speeton (Davey, 1974) et le Barremien superieur du stratotype ( M i 1 1 i o u d , 1969). V. CONCLUSIONS L’etude des dinoflagelies du contenu palynologique des formations de Svinița et Murguceva a permis d’identifier des biozones de dinoflagel- les, biozones correiables avec celles donnees par les ammonites et les cal- pionelles des memes formations. Quoique etant des biozones avec une văleni’ pour le moment locale, ces zones ont beaucoup de traits communs avec les zones de dinoflagelies etablies dans d’autres regions du monde pour le Cretace inferieur et pourront dans l’avenir servir ă l’identification de chronozones. — La biozone ă Druggidium apicopaucicum et Phoberocysta neo- comica (concurrent range-zone) dans la formation de Murguceva est corre- lable avec la pârtie terminale de la zone Calpionellopsis, la zone Calpio- nellites et avec les niveaux de calcaires ă accidents siliceux contenant Kilianella ex gr. roubaudiana et Olcostephamus spp. L’intervalle strati- graphique correspondant ă cette biozone est le Berriasien superieur-Valan- ginien. Cette biozone a ete identifice dans la pârtie moyenne des calcaires ă accidents siliceux de la formation de Murguceva, sur la coupe de Mur- guceva. Deux sous-zones ont ete identifiees dans cette biozone. Celle infe- rieure, ă Druggidium apicopaucicum, correspond ă la pârtie terminale de la zone Calpionellopsis et ă la pârtie inferieure de la zone Calpionelli- tes. L’âge de cette sous-zone est 6quivalent du Berriasien superieur- Valanginien inferieur. La sous-zone superieure est celle ă Oligosphaeridium asterigium, Polysphaeridium warreni et Biorbifera johnewingi. Elle correspond ă la pârtie superieure de la zone Calpionellites et au niveaux ă Kilianella ex gr. roubaudiana et Olcostephanus spp. L’âge de cette sous-zone correspond ă la pârtie moyenne du Valanginien inferieur jusqu’au Valanginien su- perieur y compris Le contenu en dinoflagelies de cette zone peut etre correle avec la zone ă Druggidium, apicopaucicum (Berriasien-Valanginien) du Neo- comien de l’Atlantique du Nord — 600 km Est du Cape Hatteras et du Blake Bahamas Outer Eidge System (DSDP site 105 et DSDP sites 99, Institutul Geological României 124 EM. ANTONESCU. E. AVRAM 28 100, 101; Habib, 1975) avec la zone ^Phoberocysta neocomica des formation Mississauga et Verril Canyon du Scoțian Shelf et Grand Banks de l’Atlantique canadien (W i11i a ms , 1975; B u j a k & W i 11 i a m s, 1978), avec la zone ă Phoberocysta neocomica de l’Atlantique de l'Est preș des cotes de l’Afrique au Nord-Ouest (du Plateau marocain (W i 1- 1 i a m s, 1978), partiellement (la sous-zone ă Oligosphaeridium asterigi a m, Polysphaeridium warreni et Biorbifera johnewingi) avec la zone â Bior- bifera johnezvingi de la Deer Bay Formation du Canada de l’Ouest, trou- v6e dans les depots a Thorsteinssonoceras ellesmerensis et Buchia keyser- lingi (= la zone â Kilianella roubaudima) et les d^pâts â Polyptychites keyserlingi, Tollia mutabilis et Buchia pacifica (= la zone â Saynoceras verrucosum identifiee par P o c o c k, 1976), avec le Berriasien et le Valan- ginien des stratotypes selon les dinoflagelles (M i 11 i o u d, 1969 ; Habib&Warren, 1973 cf. Habib, 1975; M i 11 i o u d, 1975 cf. Ha b i b, 1975), et partiellement avec la zone ă Phoberocysta neoco- mica du Berriasien de la Plate-forme moesienne (B a 11 e ș, 1971). — La biozone â Oligosphaeridium complex et Druggidium deflandrei (concurrent range-zone) dans la coupe de Murguceva, formation de Mur- guceva debute au-dessous du niveau â Teschenites pachydicranus, â la limite Valanginien-Hauterivien. Cette biozone est corr61able aussi sur la coupe du ruisseau Morilor avec l’intervalle contenant Spitidiscus cf. incertus, Crioceratites majoricensis, Crioceratites matsumotoi, la biozone â- Crioceratites duvali, et â la biozone â Acrioceras seringei et Paraspinoceras jourdani (la pârtie superieure de la formation de Murguceva et la pârtie inferieure de la formation de Svinița). L’âge de cette biozone correspond â l’Hauterivien. Cette biozone peut se correler part iellement avec la zone â Oligo- sphaeridium complex (d’âge valanginien-barr&nien) du Neocomien de l’Atlantique du Nord (H a b i b, 1975); avec la zone a Ctenidodinium elegantulum de l’Hauterivien de l’Atlantique de l’Est — DSDP 370 preș de la bordure du plateau marocain — les câtes de l’Afrique, par la presence de Spiniferites dentatus, Oligosphaeridium complex, Ctenidodinium elegan- tulum-, avec l’Hauterivien d’Allemagne (Gocht, 1957; 1959) et celui des stratotypes du Cretace inferieur par la composition generale de l’as- sociation. — La biozone â Dingodinium albertii et Meiourogonyaulax stoveri (peak zone) est corrMable avec les biozones â Paraspiticeras et Pseudo- thurmannia et partiellement avec la zone ă Leptoceras et Holcodiscus sur la coupe de Pîrîul Morilor, sous-formation de Pîrîul Morilor. L’âge de cette biozone est equivalent du Barremien inferieur. On peut correler cette zone avec la zone ă Dingodinium cerviculum et Apteodinium granulatum (partiellement) du Barremien de la Plate-forme moesienne (B alte ș, 1971). — La biozone ă Prolixosphaeridium, parvispinum est conAlable dans la coupe du Pîrîul Morilor, formation de Svinița, sous-formation de Pîrîul Morilor et la sous-formation de Temeneacia avec l’intervalle du sommet de la biozone â Leptoceras et Holcodiscus jusqu’â la biozone ă Imerites eh Institutul Geological României 29 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 125 Eristavia y compris. Sur les coupes de Pîrîul Țiganilor, Temeneacia, route Svinița-Orșova et le debarcadere de Svinița, la zone ă Prolixosphaeridium parvispinum correspond â l’intervalle comprenant les biozones ă, Imeri- tes et Eristavia, la biozone ă « Crioceratites» ex gr. barremense-orbignyi et celle ă Pseudohaploceras matheroni et Deshayesites weissi. L’âge de cette biozone correspond au Barr6mien superieur-Aptien inferieur. 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Geoscience and Man, VII, 47—55, 3pl., 4 text-fig., 1 tabl., New- York. — (1975) Neocomian dinoflagellate] zonation in the western North Atlantic. Micropaleon- lology, 21, 4, 373 — 392, pis. 1 — 3, New-York. II a r k c r S. D., S a r j c a n t W.A.S. (1975) The stratigraphic distribution of organic walled dinoflagellate cysts in the Cretaceous and Tertiary. Review of Palaeobotany and Paly- nology 20, 217 — 315, tabl. 1, chart 1 — 68, pl. 1, Amsterdam. I o a n n i d e s N. S., S t a v r i n o s G. N., D o w n i e C. (1976) Kimmeridgian mikroplank- ton from Clavell’s Hard, Dorset, England. Micropalenlology, 22, 4, 443 — 479, pl. 1 — 5, text. fig. 1—14, New-York. Kilian A. (1907—1913) Unterkreidc in siidostlichen Frankreichn. Lethaea geognostica II, 3? 398 p., 14 pl., Stuttgart. Koch F. (1912) Bericht liber meinc palăontologischen Aufsammlungen und stratigraphis- chen Beobachtungcn tVahrend des Sommers 1909 in der Umgcbung von Szvinica im Komitat Krassoszorcny. Jb. d, k. Geol. R.A. f. 123 — 126, Budapest. K u d e r n a t s c h J. (1852) Die Ammoniten von Swinitza. Abhandl der K. K. geol. R. A. Bd. I. Wien. L a p e y r e J.-F., T h o m e 1 G. (1974) Considerations sur la valeur et la situation stratigra- phique precise de la zone a Angulicostata (Neocomien) C. B. Acad. Sci., 278, D, 2889 - 2892, Paris. M i 1 i o u d M. E. (1969) Dinoflagellate and Acritarchs from some western European Lower Cetaceous type localities. In : Bronniman P. & Renz H. H. (eds.) : Internat. Conf. Planktonic Microfossils, 4st, Geneve, 1967, Procecdings, E. J. Brill, 2, 420 — 434, pis. 1 — 3, tabl. 1 — 3, Leiden. M u 11 e r S. W., S c h e n k H. G. (1943) Standard of Cretaceous System. Bull. Amer. Assoc. Petroleum Geologists, 27, 3, 262—278, 7, figs., Tulsa. Năstăseanu S. (1980) Geologie des Monts Cerna. Arin Inst. geol. geofiz., LIV, 153 — 280, 28 fig., 3 pl., București. Institutul Geological României 31 dinoflagelles du CRETACE INFERIEUR de svinița 127 Patrulius D. (1969) Geologia Masivului Bucegi și a Culoarului Dîmbovicioarei Ed. Acad. R. S. România, 321 p.. București. — Avram E. (1976) Stratigraphie et correlation des terrains neocomiens el barremo- bădouliens du Couloir de Dimbovicioara (Carpathes Orientales). D.S. Inst. geol. geofiz., LXII, LXII, 4, 135 — 160, 15 figs., București. Pocock S.A.J. (1976) A preliminary dinoflagellate zonation of the Upper"ost Jurassic and Lower part of the Cretaceous, Canadian Arctic, and possible correlation in the western Canada Basin. Geoscience and Man, XV, 101 — 114, 2 pl., 3 tcxt-fig., New-York, Po p Gr. (1973) Depozitele mezozoice din munții Vîlcan (The Mesozoic sedimentary formations from the Vîlcan Mts.). Area — Southern Carpathians). Ed. Acad. R .S. România, 115 p., 36 fig. 13 pl., tabl., București. Răileanu Gr. (1953) Cercetări geologice în regiunea Svinița — Fața Mare. Bul St. Acad. R.P.R., Seci. Șl. Biol-, Agronomice, Geol., Geogr., V, 2, 307— 109, 38 fig., 2 pl. București. — (1960) Recherches geoiogiques dans la region Svinița — Fața Mare. Ann. Com. Geol., XXVI-XXVIII, 347-383, 14 fig., 1 carte, București. — Popescu Gh. (1964) Studiul micropaleontologic al Cretacicului inferior de la Svinița (Banatul) de Sud). Stud. cerc. geol. geofiz. geogr. (Geol.), 9, 51 — 60, 29 fig., București. — T o d i r i ț a — M i h ă i 1 e s c u Victoria, M u ț i u R. (1969) Noi contribuții la cunoașterea Eocretacicului din regiunea Svinița și corelarea lui cu Eocretacicul din Platforma Moesică. An. Un t>. București, Geologie 127, 130, 4 p)., București. Rusu A. (1970) Biozonele de calpionele din Tithonic-Neocomianul zonei Svinița (Banat). Slud. cerc. geol. geogr (Geol.) 15, 2, 489—497, 2 fig. 4 pl., 1 tab.. București. Sarjeant W.A S. D o w n i e C. (1974) The Classification of Dinoflagellate Cysts Above Generic Levcl; a Discussion and Revision. Paleobolanist, Birbal Salini Institute Paleo- botany, Spec. Publ., 3, 9—32, Lucknow. Sarjeant W.A.S. (1974) Fossil and Living Dinoflagellates. Academic Press, London and New-Work, 1-812 p. S c n a f a r z i k F. (1894) Die gcologische Verhăltnisse der Umgebungen von Eibenthal. Ujba- nya, Țiszovicza und Svinicza. Jb., d. k. ung. geol. A. f. 1892, 140 — 159, Budapest. T h i e u 1 o y .1. P. (1965) Sur quelques exemples d’accidents de stratification dans le Neoco- mien du massif de la Grande — Chartreuse. C. R. Soni. Soc. Geol. France, 1965/1, 15 — 16, Paris. T i et z e E. (1872) Geologische und palăontologische Miltheilungen aus dem sudlichen Teii des Banater Gebirgsstockes. Jb. d. kk. geol. R. A., XXII, 35 — 142, II—IX, Wien. Uhlig V. (1883) Die Cephalopodenfauna der Wernsdorferschichten. Denkschr. k. akad. Wissenschafl. XLVI, II, 127-290, 32 pl., Wien. V e r d i e r J.-P. (1975) Les kystes de dinoflagelles de la Section de Wissant et leur distribu- tion stratigraphique au Cretace moyen. Revue de MicropaUontologie, 17, 4, 191 — 197, fig. 1 — 5, Paris. Williams G. L. (1975) Dinoflagellate and Spore stratigraphy of the Mesozoic — Cenozoic» offshore Eastern Canada. Geological Surueg Canadian 74 — 30, 2, 107 — 146, fig. 1—5, pl. 1—8, Quebc, Ottawa. — (1978) Palynological Biostratigraphy, Deep Sea Drilling Project Siles 367 and 370. Inițial Reports of the Deep Sea Drilling Pr< ject„ XLI, 783 —815, fig. 1 — 6, Washington. 'A Institutul Geologic al României IGR/ 128 EM. ANTONESCU, E. AVRAM 32 EXPLICATION DES PLANCHES Planche IV Fig. 1. — Gonyaulacysta cf. diulina D u x b u r y , 1977. Lame 7341/3 ; 12,3/109, 8 ; 53 g f. 263. Formation de Murguceva, ruisseau Murguceva. Limite Berriasien superieur-Valangi- nîen inferieur, zone â Calpionellopsis. Fig. 2.— Gonyaulacysta sp. C. Lame 7504/72; 5/99; 108jz, f. 267. Formation de Svinița, sous-formation de Pîriul Morilor, ruisseau Morilor. Barremien superieur, biozone â Pulchellia ex gr. compressissima, Spitidiscus, Holcodiscus et Leploceras. Fig. 3. —Cf. Millioudodinium sp. Lame 7500/50 ; 19,3/101,3 ; 78p, f. 270. Formation de Svinița, formation de Pîriul Morilor, ruisseau Morilor. Hauterivien, biozone â Acrioceras seringei et Paraspiticeras jourdani. Fig. L— Gonyaulacysta sp. B. Lame 7502/75; 8/120, 6; 125p.f. 269. Formation de Svinița, sous-formation de Pîriul Morilor, ruisseau Morilor. Barremien inferieur, biozone ă Paraspiticeras et Pseudothurmannia. Fig. 5. — Cribroperid’nium sp. Lame 7498/53 ; 7,4/99,1 ; 78(x, f. 270. Formation de Murguceva, ruisseau Morilor. Hauterivien, biozone â Crioceratites duvali. T ous les exemplaires figurâs se trouvent dans la collection du Laboratoire de Paleontologie de 1’Institut de Geologie et de Geophysique. Les coordonnees des exemplaires ont ete prises au microscope Zeiss-Amplival 1501311. Planche V Fig. 1. — cf. Leplodinium sp. Lame 7502/80 ; 8,5/105 ; 48jx, f. 268. Formation de Svinița, sous- formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone ă Paraspi- ticeras et Pseudothurmannia. Fig. 2. — Occisucysta sp. ex G itmez, 1970. Lame 7494/72 ; 24,1/110,9 ; 98ix, f. 267. Forma- tion de Murguceva, ruisseau Murguceva. Valanginien superieur â Oleostephanus spp. Fig.3 — cf. Cyclonepheb'um hyslrix (Eisenack) Sarjeant & S t o v e r , 1978. Lame 7497/71 ; 23/118,2 ; 63(x, f. 264. Formation de Murguceva, ruisseau Morilor. Hauteri- vien, niveau entre le niveau avec Spitidiscus, Crioceratites matsumotoi et la biozone â Crioceratites duvali. Fig. 4. — cf. Clenidodinium elcgantulum M i 11 i o u d , 1969. Lame 7497/73 ; 24/111, 2 ; 70^, f. 270. Formation de Murguceva, ruisseau Morilor. Hauterivien, niveau entre le niveau ă Spitidiscus, Cr ioceraliles malsumolo' el la biozone â Crioceratites duvali. Fig. 5. — Occisuci/sta tenloria Duxbury, 1977. Lame 7494/71; 24,5/112,8; 78p., f. 271. Formation de Murguceva, ruisseau Murguceva. Valanginien superieur â Oleostephanus spp. Planche VI Fig. 1, 2. — Druggid'um apiwpaueieam H a b i b , 1973. Lame 7341/5 ; 4,5/105,5 ; 43jx, f. 270. Formation de Murguceva, ruisseau Murguceva. Limite Berriasien superieur-Valangi- nien inferieur, zone â Calpionellopsis. 'A Institutul Geological României IGRZ 33 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 129 Fig. 3. — Druggidium deflandrei (Millioud) H a b i b , t«73. Formation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone â Paraspiticeras et Pseudothurmannia. Fig. 4. — ef. Xenicodinium densispinosum Klement, 1960. Lame 7494/72; 17/114: 75fz, f. 272. Formation de Murguceva, ruisseau Murguceva. Valanginien supferieur â Olcostephanus spp. Fig. o. — Meiourogonyaulax sloveri Millioud, 1969. Lame 7501/2; 22,7/105,6; 63jz, f. 267 . Formation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor.Limite Hauterivien-Barrâmien, biozone ă Acrioceras seringă et Paraspinoceras jourdani. Fig. 6. — Apteodinium cf. conjunclum Eisenack & Cookson, 1960. Lame 7498/50; 10,2 /109 ; 63jx, f. 270. Formation de Murguceva, ruisseau Morilor. Hauteri- vien, biozone ă Crioceralites duvali. Fig. 7. — Sentusidinium'! sp. A. Lame 7341/2 ; 15,9/99,2 ; 63;x, f. 263. Formation de Murguceva, ruisseau Murguceva. Limite Berriasien sup6rieur-Valanginien inferieur, zone â Calpio- nellopsis. Fig. 8 — Hyslrichodinium voigti (A 1 b e r t i) C 1 a r k e & Verdier, 1969. Lame 7494/71 ; 6,5 /112 ; 65p., f. 271. Formation de Murguceva, ruisseau Muiguceva. Valanginien supe- rieur â Olcoslephanus spp. Planche VII Fig. 1, 3. — Cyclonepheli'tm distinctum Deflandre & Cookson, 1955. Fig. 1, lame 7197/'71; 9,2/112,1 ; 112|i, f. 268. Formation de Murguceva, ruisseau Morilor. Hauteri- vien, niveau entre le niveau avec Spilidiscus, C. matsumotoi et la biozone â Crioce- ratites duvali. Fig. 3, lame 7497/71 ; 14,2/113,8; 98p., f. 254. Formation de Murguceva, ruisseau Morilor. Hauterivien, niveau entre le niveau â Spilidiscus, C. matsumotoi et la biozone â Crioceralites duvali. Fig. 2. — Tapeinosphaeridium pericompsum loannides, Stavrinos & D o w n i e , 1976. Lame 7341/5 ; 17/96,4 ; 60u, f. 263. Formation de Murguceva, ruisseau Murgu- ceva. Limite Berriassien superieur — Valanginien inferieur, zone â Calpionellopsis. Fig. L — Tapeinosphaeridium cf. granulalum loannides, Stavrinos & D o w n i e, 1976. Lame 7495/50 ; 15,6/110 ; 78(z, f. 266. Formation de Murguceva, ruisseau Murgu- ceva. Hauterivien â Teschenites pachydicranus. Planche VIII Fig. 1, 2. — Muderongia staurola Sarj eant, 1966. Fig. 1,lame 7194/13 ; 2,2/115,2; 125p., f. 154. Formation de Svinița, sous-format'.on de Temeneacia, Barrfemien superieur, biozone â Imerites et Eristavia. ruisseau Morilor. Fig. 2, lame 7502/72 ; 6,3/111,6 : 125p., f. 264. Formation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone â Paraspiticeras et Pseudothurmannia. Fig. 3. — Phoberocysta neocomica (Gocht) Millioud, 1967. Lame 7192/5; 2,5/99,6; 151p., f. 144. Formation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone ă Paraspiticeras et Pseudothurmannia. Fig. 4. _ Muderongia sp. cf. M. mcwhaei Cooksm & Eisenack, 1958 e.< Wall & Evitt, 1975. Lame 7502/73; 18/110,8; 160[x, f. 268. Formation de Svinița, sous- 9 — Cș 658 Institutul Geologic al României 130 EM. ANTONESCU, E. AVRAM 34 formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone â Paraspi- ticeras et Pseudothurmannia. Fig. 5. — Sentusidinium sp. B. Lame 7497/71 ; 21/105,7 ; 75[z, f. 264. Formation de Murgueeva, ruisseau Morilor, Hauterivien, niveau entre le niveau ă Spitidiscus, Crioceratites matsumotoi et la biozone â Crioceratites duvali. Fig. 6. — Pseudoceratium pelliferum G o c h t, 1957. Lame 7497/73 ; 22/120 ; 95p., f. 234. Forma- tion de Murgueeva, ruisseau Murgueeva. Valanginien superieur ă Olcostephanus spp. Planche IX Fig. 1. — Spiniferites dentatus (G o c h t) L ent in & Williams, 1973, emend. Dux- b u r y , 1977. Lame 7493/73 ; 5,9/102,2 ; 70p, f. 270. Formation de Murgueeva. ruis- seau Morilor. Hauterivien, niveau entre le niveau â Spitidiscus, Crioceratites maisu- motoi et la biozone â Crioceratites dancii. Fig. 2. — Dinoflagell4 type A. Lame 7497/74 ; 1,9/115 • 109(z, f. 272. Formation de Murgueeva, ruisseau Morilor. Hauterivien, niveau entre le niveau ă Spitidiscus, Crioceratites matsumotoi et Ia biozone ă Crioceratites duvali. Fig. 3. — cf. Amphorula melaelliptica Dodekova, 1969. Lame 7493/73 ; 12,2/118 • lOOp., f. 271. Formation de Murgueeva, ruisseau Murgueeva. Valanginien, niveau entre le niveau ă Kilianella roubaudiana et le niveau â Olcostephanus spp. Fig. 4. — Dingodinium albertii Sarj eant, 1966. Lame 7501/75; 24,7/108,6; 58p, f. 268. Formation de Svinița, sous-formation de Pîrîul Morilor, limite Hauterivien-Barre- mien inferieur, biozone ă Acrioceras seringei et Paraspiticeras jourdani, ruisseau Morilor. Planche X Fig. 1. — Polysphaeridium ivarreni Habib, 1976. Lame 7494/72; 13,8/123,3; 70;a, f. 272. Formation de Murgueeva, ruisseau Murgueeva. Valanginien supărieur a Olcoste- phanus spp. Fig. 2. — Sentusidinium? sp. B. Lame 7503/7 ; 24,5/109,2 ; 50/z, f. 269. Formation de Svinița, sous-formation de Temeneacia, ruisseau Morilor. Barremien inferieur, biozone ă Paraspiticeras et Pseudothurmannia. Fig. 3. — Baltisphaeridium sp. B ex Singh, 1972. Fig. 4. — Spiniferites ramosus (Ehrenberg)MantelI, 1854 subsp. ramosus D a v e y & Williams, 1966. Lame 7192/4L 16/120,1; 60[Z, f. 144. Formation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone â Paraspiticeras et Pseudothurmannia. Fig. 5. — Polysphaeridium cf. laminaspinosum D a v e y & W i 1 i a m s , 1966. Lame 7494/73 ; 18,9/101,9 ; 63(z, f. 267. Formation de Murgueeva, ruisseau Murgueeva. Valangi- nien superieur â Olcostephanus spp. Fig. 6. — Sentusidinium? sp. G. Lame 7495/1 ; 14,5/118,1 ; 51 pi, f. 157. Formation de Murgueeva, ruisseau Murgueeva. Hauterivien ă Teschenites pachydicranus. Planche XI Fig. 1. — Kleithriasphaeridium fasciatum (D a v e y & W i 11 i a m s ) D a v e y, 1974. Lame 7198/52 ; 23/108,7 ; 70fz, f. 268. Formation de Murgueeva, ruisseau Morilor. Hauteri- vien, biozone â Crioceratites duvali. Institutul Geological României 35 DINOFLAGELLES DU CRETACE INFERIEUR DE SVINIȚA 131 Fig. 2. — cf. Broomea sp. Lame 7502/72 ; 4/105 ; lOOp, f. 264 Formation de Svinița, sous-for- mation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone â Paraspiti- ceras et Pseudothurmannia. Fig. 3. — cf. Senlusidinium? atlanticum (Habib) Sarjeant & Stover, 1978. Lame 7197/73 ; 9,8/110,2; 43p, f. 270. Formation de Murgueeva, ruisseau Morilor. Hauteri- vien, niveau entre le niveau â Spitidiscus, C. malsumotoi et la biozone â Crioceratites duoali. Fig. 4, 6. — Prolixosphaeridium parvispinum (Deflandre) Davey, Downie, S a r- j ea n t & Wil lia m s , 1966. Fig. 4, lame 7507/71 ; 116,8 ; 70 p, f. 266. Fig.6, lame 1616/2 ; 2/106 ; 73p, f. 148. Foination de Svinița, sous-formation de Temeneacia, ruisseau Morilor. Barr&nien superieur, biozone â Imerites et Eristavia. Fig. 5. — Wallodinium krutzschi (Alberti) Habib, 1972. Lame 7341/2; 14,5/99; 98p; f. 263. Formation de Murgueeva, ruisseau Murgueeva. Limite Berriasien- Valanginien, zone â Calpionellopsis. Planche XII Fig. 1, 3. — Oligosphaeridium complex (VI hi t e) D a v ey & Williams, 1966 (in D a v e y, D o w n ie S a r j e a n t & W i 1 i a m s ). Fig. 1, lame 7497/71 ; 16,4/119,9 ; HOp, f. 268 Formation de Murgueeva sous-formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone â Paraspiticeras et Pseudothurmannia. Fig. 3, lame 7192/4 ; 14,8/11 ; 143p, f. 153. Formation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor. Barremien inferieur, biozone â Paraspiticeras et Pseudothurmannia. Fig. 2. — Oligoshaeridium asterigium (Gocht) Davey & Williams, 1966. Lame 7498/52 ; 7/110 ; 112p, f. 270. Formation de Murgueeva, ruisseau Morilor. Hauterivien, biozone ă Crioceratites. Fig. 4. — Oligosphaeridium cf. diastema S i n gh, 1971. Lame 7502/72 ; 15,2/110,7 ; 93p, f 264. Formation de Svinița, sous-formation de Pîrîul Morilor. Barremien inferieur, biozone ă Paraspiticeras et Pseudothurmannia. Fig. 5. — Cassiculosphaeridia magna Davey, 1974. Lame 7493/73 ; 18,2/119,2 ; 65p, f. 271. Formation de Murgueeva, ruisseau Murgueeva. Valanginien, niveau entre le niveau â Kilianella roubaudiana et le niveau â Olcostephanus spp. Fig. 6. — Batioladinium sp. Lame 7497/72; 2,4/108,5; 80p, f. 270. Formation de Murgueeva, ruisseau Morilor. Hauterivien, niveau entre le niveau ă Spitidiscus., C. malsumotoi et la biozone â Crioceratites duvali. Fig. 7. — Achomosphaera neptuni (Eisenack), Davey& Williams, 1966. Lame 7494/71; 11,1/127,2 ; 83p, 1. 277. Formation de Murgueeva, ruisseau Murgueeva. Limite Berriasien-Valanginien superieur, zone â Calpionellopsis. Planche XIII Fig. 1. - Prolixosphaeridium? sp. A. Lame 7341/2 ; 17,3/118 ; 63p, f. 263. Formation de Murgu- ceva, ruisseau Murgueeva. Limite Berriasien-Valanginien, zone â Calpionellopsis. Fig. o. - Cleistosphaeridiuml sp. A. Lame 7494/74, 14/107,5 ; 95p, f. 272. Formation de Murgu- ceva, ruisseau Murgueeva. Valanginien ă Olcostephanus spp. Fig. 3. — Tanyosphaeridium sp. A. Lame 7494/76 ; 11/114,6 ; 48 p, f. 271. Formation de Murgu- ceva, ruisseau Murgueeva. Valanginien superieur ă Olcostephanus spp. Institutul Geological României 132 EM. ANTONESCU, E. AVRAM 36 Fig. 4. Fig- 5. Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Tanyosphaeriditun sp. B. Lame 7503/71 ;18,3/125,1 ; 48p, f. 269. Formation de Svinița, sous-formation de Temeneacia, ruisseau Morilor. Barremien superieur (biozone non- definie). - Comelodinium ? sp. Lame 7501/76; 7/102,2; 80 p, f. 268. Formation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor. Limite Hauterivien-Barremien inferieur, biozone â Acrioceras seringei et Paraspiticeras,. Planche XIV Biorbifera sp. A. Lame 7494/72 ; 22,8/108,5 ; 40p, f. 271. Formation de Murguceva, ruisseau Murguceva. Valanginien superieur â Olcoslephanus spp. — Apteodinium cf. conjunctura Eisenack &Cookson, 1960. Formation de Murguceva, ruisseau Morilor. Hauterivien, niveau entre le niveau â Spitidiscus, Crioceratites matsumloi et la biozone â Crioceratites duoali. - cf. Pterospermopsis sp. Lame 7341/2 ; 14/98,4 ; 48p, f. 263. Formation dc Murguceva ruisseau Murguceva. Limite Berriasien-Valanginien inferieur, zone â Calpionellop- sis. — cf. Operculodinium sp. Lame 7497/72 ; 10,8/111,5 ; 70p., f. 270. Formation de Murgu- ceva, ruisseau Morilor. Hauterivien, niveau entre le niveau ă Spitidiscus, C. matsu- motoi et la biozone â Crioceratites duvali. - Cassiculosphaeridia magna Davey, 1974. Lame 7501/76 ; 10/116 ; 63p., f. 269. For- mation de Svinița, sous-formation de Pîrîul Morilor, ruisseau Morilor. Limite Haute- rivien-Barremien inferieur, biozone â Acrioceras seringei et Paraspinoceras jourdani. - Biorbifera johnewingi Habib, 1972. Lame 7494/72 ; 14,9/98,2 ; 53[X, f. 675. Forina- tion de Murguceva, ruisseau Murguceva. Valanginien supărieur â Olcostephanus spp. — cf. Adnatosphaeridium sp. Institutul Geological României EM. ANTONESCU. E. AVRAM - Dinoflagelles du Cretace inferieur de Șvinița PI.1I Svinița-debarcadere RUISSEAU MORILOR REPARTITION DES AMMONITES ET DINOFLAGELLES SUR to 05 r10m -5 L0 B Sommun tO-IOOexemp/aires Tres rare 1 exemplaire ■ Rare MOexemplaires tres © 7^36 Niveau de pre/evement des Omoflagellees ANUARUL INSTITUTULUI DE GEOLOGIE Șl GEOFIZ IC A. VOL LVI 03 03 Accidenta siliceux Niveau de pre/evement des Cephalopodes Legende Calcaires en plaques, parfois schisteux Calcaires marneux Marnes et argiles marneuses Mar no - calcaires \ Institutul Geologic al României IGR/ • cr B ă„Crioceratites'] gr. barremease - orbignyi 8. a Imeri- tes et Eristavia Route Svinița - Spitidiscus cf mcertus Crioceratites majoncensis Crioceratites matsumotoi V2/1 , vf VI Cr. cf du va li -Confluence EM. ANTONESCU, E. AVRAM - Dinoflagelles du Cretace inferieur de Svinița REPARTITION STRATIGRAPHIQUE DES AMMONITES, CALPIONELLES ET DINOFLAGELLES SUR LE RUISSEAUX ȚIGANILOR, TEMENEACIA, VERSANT DROIT DU RUISSEAU MORILOR, ROUTE SVINITA-ORSOVA ET SVINIȚA-DEBARCADERE 9 f 9 Si/zn/ta - z debarcadere 7993 " Lrr.-—------ /toate Swnifa- rlOm -5 LO s2k- L egende z Marnes et argi/es Manno - ca/ca/re s 7795 //z/eau de pre/evement des Cepha/opodes N/veau de pre/evement des D/nof/age/fes 100 % 0 50 I I I I t I I 7res rare; 1 exemp/a/re fiare /-10 exemp/azres CommundO-100 exemp/azres ANUARUL INSTITUTULUI DE GEOLOGIE Șl GEOFIZICA VOL. LVI IGR Abordant >/OO exemp/a/res Imprim. Atei. Inst. Geol. Geof. Ui I o O X Group 3.1 : Nature of the Flysch Geosynclines TIME OF FLYSCH DEPOSITION IN THE EASTEEN CAEPATHIANS1 M11IAI ȘTEFĂNESCU2 Flysch. Eithostratigraphy. Tithonian-Loiver Miocene. East Carpathians. Transcarpathian flysch. Crystalline-Mesozoic Zone. Internai flysch. Externai flysch. Sommaire Temps de deposition du flysch dans lesCarpathcs Orienta- les. Le segment oriental des Carpathes presente de larges surfaces, sur lesquelles affleurcnt des depots â facies de flysch. I/objet de la presente etude est de presenter les principales etapes (Tithonique superieur-N6ocomien, Barremien-Aptien, Albien-Vraconien inferieur, Vra- conien superieur-Turonien, Senonien-Eocene, Oligocene-Miocene inferieur) de râvohition du geosynclinal, au cours desquelles se sont accumules des depâts â facies de flysch, y compris les aspects les plus caracteristiques des ceux-ci. Introduetion Between the northern border of Eomania and the Dîmbovița Valley, the Eastern Carpathians, as inost of the Alpine regions, display a well marked longitudinal zonality. Four zones individualize on their territory, which, from the inner (west) towards outer (east) part, are the following : the Volcanic zone, the Transcarpathians zone, the Crystal- line-Mesozoic zone and the Flysch zone (Fig.). Excepting the Volcanic zone, all the three others show a very advanced structure, characterized by the presence of large nappes, each of them having its own litho-stra- tigraphic sequence. The deposits in flysch facies are not developed on the whole litho-stratigraphic column of the same tectonic unit, but they occur at one or severa! levels. To illustrate the stratigraphic position of 1 Paper received on Mărcii 17, 1980 and accepted for publication on Mărcii 23, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. Institutul Geologic al României 134 M. ȘTEFĂNESCU 2 different flysch volumes we worked out the synopsis in Plate. We want to emphasize that this synopsis was made up on the basis of some other tables, whose authors are the following : Patrulius, Lupu, Jana Săndulescu (1971), S ă n d u 1 e s c u, Emilia Saulea, Jana Săndulescu (1971), Ștefănescu (1976, annexes in Ștefănescu et al., 1979). Fig. — Sketch showing the distribution of the main tectonofacial zones in the Eastern Carpathians. 1, volcanic zone ; 2, Transcarpathian zone ; 3a, Crystalline-Mesozoic zone; 3b, intermediate units; 4, flysch zone: a, inner subzone; b, outer sub- zonc : 5, foredeep ; 6, depressions. Opinions about the distribution of the different types of deposits and implicitely of the flysch ones from the Eastern Carpathians were expressed by the following authors : B ă n c i 1 ă (1958), Murgeanu et al. (1961), Dumi tr e s cu et al. (1962), Conte seu (1967, 1974), Mihăilescu (in Slaska, 1976), Săndulescu (1975), Patru- lius et al. (1968, 1976), Ștefănescu et al. (1979). Remarks on the Stratigraphie Position oî the Flysch Deposits The flysch deposits on the Romanian territory of the Eastern Carpathians began accumulating since the end of the Jurassic, more precisely during the Upper Tithonian and only in the flysch zone. Thus they outerop today only in the inner part of this zone, namely in the black flysch nappe and the Ceahlău one. A shally-sandy flysch (black flysch — B 1 e a h u , 1962) overlies normally a basement of 3 TIME OF FLYSCH DEPOSITION — EAST CARPATHIANS 135 basic rocks (Săndulescu, 1975) in the Black flysch nappe. The oldest deposits known in the Ceahlău nappe are the Sinaia beds. The latter begin with Upper Tithonian, more or less limy pelagic shales-pre- flysch deposits. One should mention that the preflysch and flysch depo- sits belonging to the lower part of the Sinaia beds are associated with red and green phyllites, radiolarites and basic rocks (Azuga “beds”). The highest level with basic rocks has an outer equivalent level in which the marly limestones intercalated in the flysch contain cherts. Taking into account the distribution and age of the basic rocks one may consider that the emission zone (“rift”) of these rocks was placed between the outer part of the black flysch nappe (the Socolău-Rica tectonic scale) which contains the youngest eruptions and the inner part of the Ceahlău nappe. The stratigraphic interval corresponding to the Neocomian contains important piles of deposits in flysch facies that deposited both in the Crystalline-Mesozoic zone (Bucovinian nappe) and the flysch zone (the Ceahlău nappe). During this interval, in the outer trough of the Buco- vinian nappe domain, there deposited a calcarenitic shally flysch (Pojo- rîta flysch) whose age does not exceed the Valanginian (Săndulescu, 1973). In the internai trough of the same domain scarce deposits in flysch facies occur towards the upper part of the Lunca beds (Hauteri- vian). Two tectonic units (Vîrghiș and Baraolt), whose paleogeographic position is difficult to establish, outcrop between the Crystalline-Mesozoic zone and the flysch zone. These two units, called intermediate (Ștefă- nescu, Marina Ștefănescu, 1979) include almost exclusively deposits in flysch facies which, for the Neocomian interval, are developed in a sandy-shally facies characterized by the presence of marly limestones and polymictic breccias. Outwards the flysch deposition continues in the innermost part of the flysch zone, namely in the black flysch nappe area, where a shally-sandy flysch accumulated. The deposition of the Sinaia beds continued in the paleogeographic zone corresponding to the Ceahlău nappe. Mention should be made of the fact that in the outer part of the Ceahlău nappe, in the Upper Neocomian, an important litho- logical change takes place, namely the complete disappearance of the marly limestones. Throughout the following stratigraphic interval, the Barremian- Aptian respectively, in most cases the flysch deposits show a continuity of sedimentation, excepting the Crystalline-Mesozoic zone, where such deposits occur sporadically. Thus in the central part of the Eastern Carpathians, in the inner trough of the Bucovinian nappe domain, a sandy-shally flysch with marly limestones (the Sălămaș Formation; Patrulius et al., 1976) overlying the Lunca beds accumulated only during the Barremian. Also on the Bucovinian nappe domain, but this time in the Southern part of the Eastern Carpathian bend, a sandy or sandy-shally flysch deposited during the Aptian which, in the northern part of the same area, changes laterally into a shally flysch with calcare- nites (the flysch with Orbitolines ;P atruliu s et al., 1966). One should (kp-r Institutul Geologic al României igr/ 136 M. ȘTEFĂNESCU 4 notice that the conglomerates associated with in situ Urgonian buildups grade upwards into the before-mentioned flysch. Different sedimentation conditions existed on the territories corresponding to the intermediate units. Thus, while (shally) flysch deposits occur only in the outer part of the Vîrghiș unit, the Barremian-Aptian deposits are widespread sho- wing a sandy flysch facies in the Baraolt nappe. In the black flysch nappe domain there deposited a sandy-shally flysch characterized by the parallel lamination of its sandstones. As one would expect, in the flysch zone there existed optimum and varied conditions for the deposition of the formations under discus- sion. Sandy, sandy-shally and even shally types of flysch deposited in thick piles here, being in various relations with one another. They may be found in stratigraphic sequence: the shally—calcarenitic flysch of the Comarnic beds together with the shally flysch of the Vîrful Rădăcinii beds are overlain by the Aptian “sandy flysch facies” in the outer part of the Bratocea digitation of the Ceahlău nappe; the sandy flysch of the Bistra beds overlain by the shally sandy flysch of the Babșa beds. Lateral facies interfingerings, such as that from the Bratocea digitation, where the Aptian sandy flysch facies changes inwards to the shally flysch of “the Piscu cu Brazi beds” may be also found. At various levels the Barremian-Aptian flysch includes intercalations of conglomerates and breccias, of which those belonging to the Bistra beds and the upper part of the Piscu cu Brazi beds (Tesla level) should be mentioned. The Albian-Lower Vraconian represents an interval characterized by an important outward (eastwards) migration of the internai depositio- nal basins that offered favourable conditions to the accumulation of the deposits in flysch facies. Thus the innermost Albian-Lower Vraconian deposits in flysch facies are known outside the Ciuc digitation, where sandy or sandy-shally flysch deposits (Sin Martin Bodoc flysch and Bobu se- ries) accumulated. Ă particular feature of the above-mentioned deposits consists in the presence of some conglomerate intercalations with large len- ticular development, formed as a result of the depositions of some sub- marine fans. The best example in this sense is represented by the conglo- merates intercalated in the Bobu series and which latterally interfinger with sandy flysch deposits. The same conglomerates grade upwards into a shally flysch (Lower Vraconian), which in its turn grades upwards into pelagic deposits. The shally-sandy and sandy-shally flysch (the lithological back- ground of the Teleajen and Macla series) or even the sandy flysch (Cotum- ba sandstone, Sita-Tătara sandstone) accumulate on the areas corres- ponding to the Teleajen and Macla nappes. A common feature of these deposits is the large development of the Te unit of the Bouma. cycle (even in some massive sandstones). In the more externai areas, that is the Audia nappe and the exter- nai subzone of the flysch zone there deposited either sandy (glauconitic sandstones in the Audia nappe and the internai part of the Tarcău nappe) or shally flysch (Streiu beds in the nappe of Marginal Folds). Institutul Geological României \jgr7 5 TIME OF FLYSCH DEPOSITION — EAST CARPATHIANS 137 It should be noted that the glauconitic sandstones represent the oldest and one of the rare cases of oligomictic flysch, namely quartzose flysch. The next stratigraphic interval — Upper Vraconian-Turonian — is marked both by continuity of sedimentation and a restricted area in which flysch deposits accumulated. The most internai deposits in flysch facies in this stratigraphic interval occur in the Bodoc digitation of the Ceahlău nappe and are represented by a shally flysch. Outwards, in the Bobu unit, they are replaced by pelagic deposits (Dumbrăvioara series) which extend up to the internai part of the Teleajen nappe. In the median and externai parts of the Teleajen nappe the sandy-shally flysch facies appears again containing thick intercalations of sandy flysch (Ciugheș sandstone, Măciucu Berții sandstone). A shally or more rarely shally-sandy flysch with red and black politic intercalations (Macla series) deposited immediately outwards, in the zone corresponding to the Macla nappe. It is replaced again by pelagic deposits eastwards. Even more outwards the deposits in flysch facies are found again in the nappe of Marginal Folds, where they are represented both by a shally flysch (Streiu beds) and a siliceous shally- sandy flysch (lower member of the Tisaru beds). At the boundary between the Turonian and Senonian, more preci- sely after the Coniacian (Ștefănescu, 1971) important tectonic movements take place causing both the shortening of the crust in the inner part of the flysch zone and remarkable paleogeographic changes. These movements are followed by a new stage of strong subsidence that manifested both outside and inside the Crystalline-Mesozoic zone. These phenomena favoured both the gradual resumption of the accumu- lation conditions of the deposits in flysch facies, where they had disap- peared (internai flysch subzone), and the formation of some new accumu- lation basins of these deposits (Transcarpathian zone). Therefore the second major cycle (Săndulescu, 1975) of the flysch evolution on the Romanian territory begins during the Senonian. Although the subsidence begins during the Senonian, the deposits in flysch facies do not appear on the whole submarine area. For instance, in the Romanian sector of the Transcarpathian zone the Senonian flysch facies is absent (Săndulescu, 1975). Also, excepting the area of the Audia nappe, only pelagic formations deposited on the rest of the territory corresponding to the flysch internai subzone. The most internai part of the flysch zone, in which deposits in flysch facies occur, is the Audia nappe, where the older pelitic deposits are overlain by a thick pile of sandy flysch with shally-sandy flysch intercalations (Siriu sandstone). At last, most of the flysch deposits accumulated during the Senonian, are to be found on the territory of the Tarcău nappe. Generally shally-sandy flysch deposits (Horgazu beds, Hangu beds) occur here, having as com- mon feature the limy character. Large volumes of deposits in flysch facies accumulate during the Paleocene-Eocene, both in the Transcarpathian zone and the flysch zone. L- Institutul Geologic al României 138 M. ȘTEFANHSCU 6 As a consequence of the subsidence increase which started in the Senonian, during the Paleocene the deposits in flysch facies cover larger areas than those in the Senonian. They may be formed in : the Dragovo- Petrova nappe and Botiza nappe from the Transcarpathian zone; the Ceahlău, Bobu, Teleajen and Macla nappes from the flysch zone (espe- cially in the Eastern Carpathian bend area). The Paleocene deposits outcropping in the above-mentioned units are represented by a single flysch type, namely shally (more rarely shally-sandy or only locally with intercalations of sandy flysch) containing violaceous or red pelites. Still two exceptions are worth mentioning : the most externai northern part of the Tarcău nappe, where a sandy flysch occurs (Putna beds) and the nappe of the Marginal Folds outcropping in the Bistrița half-window, where a shally and shally-sandy flysch with black pelites (Runcu beds) exists. The deposits in flysch facies accumulated also in the Eocene in all the zones where they were present during the Paleocene too. Thus in the Transcarpathian zone (the Dragovo-Petrova and Botiza nappes) there appear shally-sandy flysch deposits (hieroglyphic type beds ; Săndu- lescu, 1975) which contain sandy flysch intercalations. A large variety of deposits accumulated in the flysch zone, all of them displaying a common, shally-sandy flysch lithological background : the lower flysch member of the Șotrile facies, the Colți-Valea Bea facies, Podu Secu beds, Plopu beds, etc. On this lithological background, by an important supply of detrital material a sandy flysch formed. This type of sandy flysch can be more developed as in the case the Tarcău sand- stone, orless developed as in the case of the jghiabu Mare beds, Pălti- noasa sandstone and Lucăcești sandstone. The low supply of detrital material determined the formation of some shally flysch deposits such as the upper flysch member of the Șotrile facies and the Vițeu beds. Towards the end of the Eocene, a general decrease of the supply of detrital material took place (probably due to the strong subsidence decrease; Ștefă- nescu, 1978)3, being accompanied by the prevalence of the normal pelagic sediment that deposited in marly or marly-limestone beds (with Globigerina). This phenomenon is remarkable by its presence throughout the flysch zone. The Oligocene-Lower Miocene (NM2_3) interval starts with non-flysch deposits as a result of the subsidence closing. After an interruption corres- ponding to the Lower Oligocene, the subsidence resumes, determining the appearance of the flysch facies once more, but only on certain territo- ries. Thus in the internai flysch subzone, in the area corresponding to the Șotrile facies, the conditions of the flysch formations do no longer appear during the Oligocene-Lower Miocene. On the other hand, deposits displaying all the characteristics of the flysch facies begin accumulating 3 Ștefănescu M. (1978) Stratigrafia și structura flișului cretacic și paleogen dintre Valea Prahovei și Valea lălomiței. Thesis of Doctor’s degree. University of Bucharest. Unpu- blished. Institutul Geological României 1GRZ 7 TIME OF FLYSCH DEPOSITION — EAST CARPATHIANS 139 again in the externai flysch subzone, corresponding to the Tarcău nappe and the internai part of the nappe of the Marginal Folds. In the internai part of the Tarcău nappe there formed a sandy-shally flysch or even inclu- ding graywacke sandy flysch intervals (the member of the Pucioasa beds with Fusaru sandstones) that interfingered with a generally sandy- quartzose flysch facies (the lower member of the Kliwa sandstone). The dark-coloured pelites, both of the Pucioasa beds with Fusaru sandstone and Kliwa sandstone facies, indicate a deposition environment in a closed basin, with restricted cii'culation. At the Oligocene-Lower Miocene boun- dary, with the first thrust phase of the Cretaceous flysch nappes over Tarcău nappe a sudden opening of the basin takes place determining the deposition of a predominantly shally-sandy flysch with gray pelites almost throughout the externai flysch subzone. The main characteristic of this type of flysch is the large development of the convoluted lamination into arenites. These flysch deposits are gradually replaced by deposits in non-flysch facies, first in the externai zones and then in the internai ones, this phenomenon becoming general later. Flysch deposits in this stratigraphic interval are altogether absent, being laterally replaced by massive conglomerates and sandstones in the most externai zones. One should note the fact that the ceasing of the accumulation of the deposits in flysch facies in the Eastern Carpathians takes place imme- diately after the deposition of some typical flysch deposits (Vinețișu beds and Podu Morii beds) that grade upwards very rapidly into non-flysch depotsits. In the Transcarpathian flysch zone, apart from some supposed Oligocene sandy flysch deposits from the Botiza nappe, thick piles of deposits in sandy flysch facies (Borșa sandstone) accumulate in the subsi- dent trough situated on the western side of the Crystalline-Mesozoic zone. The accumulation of the deposits in flysch facies stops definitively both in the flysch zone and the Transcarpathian zone, simultaneously, during the Lower Miocene. General Remarks The basement of the basins in which the deposits in flysch facies from the Eastern Carpathians accumulated is very little known, namely the autochthonous part of the Transcarpathian flysch and the flysch belonging to the Crystalline-Mesozoic zone, where it is clearly of conti- nental nature. Concerning all the other regions where the deposits in flysch facies are implied in large rootless overthrusts, there are only hypotheses based on several data such as the presence of some basic eruptive rocks associated with sedimentary rocks or the elements reworked in flysch. Thus, the following types of basement of the basins containing flysch deposits were deduced west-eastwards : oceanic for the Botiza nappe (Săndulescu, 1975, 1980); continental for the Wildflysch and Dragovo-Petrova nappes (Săndulescu, 1975); continental for the Vîrghiș and Baraolt nappes (Ștefănescu, Marina Ș t e f ă - ■ Institutul Geologic al României igr/ 140 M. ȘTEFĂNESCU 8 nes cu, 1981); oceanic for the black flysch nappe (Eădul eseu, Săndulescu, 1973) and the Ceahlău nappe (Eădulescu, Săn- dulescu, 1973) and continental for the other units in the flysch zone. The following problems may be discussed in connection with the out- ward extension of the oceanic type basement under the Ceahlău nappe : mesozonal metamorphic rocks which do not outcrop in the Crystalline- Mesozoic zone are reworkd in the externai part of the Bratocea digita- tion, which made geologists (Patrulius, 1969) admit the existence of a cordilliera type source (consisting both of metamorphic schists and Meso- zoic limestones) which is situated outside this subunit; sedimentary klip- pes of basic rocks that could not be transported from the Carpathians are to be found more outwards, in the Secăria digitation. Taking into account these data it can be admitted either that an oceanic basement, on which “icebergs” of continental crust floated, existed under the w'hole Ceahlău nappe domain or, rather that the deposits of the Ceahlău nappe (at least those lying under the externai part of the Bratocea digitation out- wards) accumulated on the basement of continental na ture. The latter must have been thin enough to allow the strong subsidence of the basin on the one hand and to permit the basic rocks to rise to the surface on some alignments which are more externai than those that existed in the formation area of the Azuga beds, on the other hand. Six different accumulation stages of the deposits in flysch facies may be distinguished in the evolution of the Eastern Carpathians. The first two stages (Upper Tithonian-Neocomian, Barremian-Aptian) can be recognized both in the Crystalline-Mesozoic zone and the flysch zone. The next two stages (Albian-Lower Vraconian and Upper Vraconian-Turonian) are typical of the flysch zone. The last two stages (Senonian-Eocene and Oligocene) manifested in the Transcarpathian zone and the flysch zone. The oldest deposits in flysch facies are of Upper Tithonian age, while the younger ones are of Lower Miocene age (NN2_3). The Tithonian-Neocomian and Eocene flysch deposits are the most widespread. The flysch deposits accumulated during the Turonian show the most reduced distribution. The sequences displaying the greatest continuity of sedimentation of the deposits in flysch facies are found in the externai part of the Ceahlău nappe and develop along the whole Neocominan-Cenomanian interval and in the Teleajen nappe in the Aptian-Turonian. The younger flysch deposits are marked by interruptions of their continuity of sedi- mentation. The deposits preceding or following eonformably the flysch facies are usually pelitic (pelagic), more or less shally. There are also some exceptions : the presence of some ruditic rocks (breccias and conglome- rates) in the normal basement of the flysch deposits (especially in those connected with the Crystalline-Mesozoic zone); the existence of the elastic deposits of Wildflysch type or olistostroma type in the top of the flysch facies. Institutul Geological României IGR/ o TIME OF FLYSCH DEPOSITION — EAST CARPATHIANS 141 The existing types of flysch in the Eastern Carpathians depend on : the subsidence rate which is higher for the sandy types and lower for the shally ones; the naturc of the supplying sources that provided the depositional basins with the detrital material consisting of polymictic (graywacke) arenites for the flysch deposits with sources of Carpathian nature or of Moesian Platform type (some coarse rocks in the Teleajen nappe) and predominantly siliceous arenites for those having Dobrogean type sources. In connection with this situation one should note the fact that the types of flysch containing arenites and rudites with Carpathian material migrate outwards in time invading the areas covered by the types of flysch containing Dobrogean type detrital material. Special mention should be made of the fact that the Tithonian-Neoco- mian and Senonian limy types of flysch or only the intervals with marly- limy or limy rocks from the Eocene flysch correspond to some periods in which the climatic conditions favoured the formation of some organic buildups in the marginal zones of the Carpathian geosyncline. Finali y we want to emphasize the fact that in the areas under discus- sion the subsidence variability brought about or not the accumulation of the deposits in flysch facies, while the subsidence of basins migrated outwards according to the polarity rule that governs the geosyncliries’ evolution. REFEEENCES Băncilă I. (1955) Geologia Carpaților Orientali. Edit. Științifică, București. Bleahu M. (1962) Cercetări geologice în bazinul superior al văii Ruscovei (Munții Maramure- șului). D. S. Com. Geol., XLV, București. Contescu L. (1967) Formations et facies dans la zone du Flysch des Carpathes Orienta- les Roumaines. Sond. a.d. Geol. 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(1969) Geologia masivului Bucegi și a culoarului Dîmbovicioarei. Edit. Acad. R.S.R., București. 142 M. ȘTEFĂNESCU 10 Patrulius D., Lupu M., Săndulescu Ja na (1971) Corelări stratigrafice ale Cre- tacicului din România. Atlas litofacial, IV, Cretacic. Inst. geol.. București. Patrulius D., Neagu Th., AvramE., Pop Gr. (1976) The Jurassic-Cretaceous Boundary Beds in Romania. An. Inst. geol., geofiz., L, București. Radul escuD. P., Săndulescu M. (1973) The Plate-Tectonics Concept and the Geolo- gical Structure of the Carpathians. Tectonophysics, 16, Amsterdam. Săndulescu M., Saulea Emilia, Săndulescu Jana (1971) Corelări strati- grafice ale Paleogenului din România. Atlas litofacial, V, Paleogen, Inst. geol., București. Săndulescu M. (1973) Contribuțiila cunoașterea structurii geologice a sinclinalului Rarău (sectorul central). D. S. Inst. geol., XLIX, 5, București. Săndulescu M. (1975) Essai de synthăse structurale des Carpathes. B.S.G.F., 7, XVII, Paris. Săndulescu M. (1980) Sur certains problemes de la correlation des Carpathes Orientales roumaines avec les Carpathes ucrainiennes. D.S. Inst. geol. geofiz., LXV/5, București. S la ska A. (1976) Atlas of Paleotransport of Detrital Sediments in the Carpathian-BaIkan Mountain System. Part. I: Tithonian-Lower Cretaceous, Warszawa. Ștefănescu M., Săndulescu M., Mi cu M. (1979) Flysch Deposits in the Easlern Carpathians. Guidebook for the Field Works of the Group <3.1. Com. Probi. IX, Geosyn- clinal Process and Earth Crust Formation, I.G.G., Bucharest. Ștefănescu M„ Ștefănescu Marina (1980) Date geologice de detaliu privind sec- torul dintre valea Covasău și valea Vîrghișului și implicațiile lor regionale. D. S. Inst. geol. geofiz. (1978—1979), București (in press). Institutul Geological României THE NATURE AED COMPOSITION OF ROMANIAN ZEOLITES1 BY GHEORGHE ISTRATE2 Zeolites. Hydrothermal alteration. Volcanic tuffs. Neogene. Trace elements. Chemical com- position. Romania. Sommaire La na tu re et la composition des zdolites de Roumanie. Les •zeolites les mieux 6tudi6es et reprâsentCes en Roumanie sont connues depuis longtemps, spe- cialemcnt cn association avec les roches ăruptives alt6r6es, dans des conditions hydrothermales appartenant aux trois provinces pttrologiques alpines : ophiolites măsozoîques, roches volca- niques'plutoniques, d’âge tertiaire inferieur (banatites) et volcanites neogenes. Les recherches les plus recentes ont mis en Evidence d’importants d6p6ts zăolitiferes provenant de l’altăration du materiei vitreux des tufs volcaniques nGogtnes, en systeme hydrologique ouvert. Moins bien reprCsentces sont les zeolites des terrains cristallins faiblement mătamorphises. On presente les donnees concernant la composition chimique et les teneurs des el6ments en traces pour les zcolites les mieux reprăsentăes : natrolite, mesolite, scolâcite, stilbite, heulandite.clinoptilolite, laumontite, mordfenite et chabazite. Introduction Zeolites were first mentioned in Romania more than a eentury ago (Ac kne r, 1855 ; Zepharovich, 1859) as products of hydrother- mal alteration of magmatic origin. This early works, now of historic inte- rest, reported analcime, chabazite, gmelinite, stilbite, heulandite, epistil- bite, laumontite and natrolite. Numerous additional discoveries are to be mentioned during the last two decades, such as the identification of a zeolite deposit in the Bihor Mountains, developed in crystalline schists under the influence of hydrothermal metamorphism generated by Early Tertiary banatitic intru- .sions (Giușcă, 1945), as well as the description of laumontite near 1 Paper received on April 6, 1980 and accepted for publication on April 9, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. Institutul Geological României \IGR 144 G. ISTRATE 2 Brad, within the domain of Neogene volcanics (B o r c o ș , 1960) and of laumontite of Ruschița, geneticalîy related with banatites (K r â u t n e r and Alexandrina Medeșan, 1966). During the last few years many zeolite occurrences in the Apuseni Mountains — the most characteristic zeolite region of this country — have been thoroughly studied by modern methods; in this area all of the above-mentioned zeolites have been recognized as well as mesolite, natro- lite, scolecite, chabazite, mordenite and heulandite (B e d e 1 e, a n , 19723 ; I s t r a t e and Alexandrina Medeșan, 1977 ; I s t r a - t e , 1980 ; Istrate et al., 1980). In addition clinoptilolite is reported — occasionally in large quantities — in the Miocene tuffs of the Tran- sylvanian Basin (Popescu and As vadur o v, 1978), as a product of the reaction of volcanic glass with meteoric water in open hydrologic Systems. Subsequently the author discovered large quantities of morde- nite and clinoptilolite in rhyolitic lavas and tuffs at Deva, Hărțăgani, Gurasada and Ciceu-Dej, whose origin is similar. New Data on the Zeolite Nature and Occurrences Almost all reported zeolite occurrences represent minerals formed under hydrothermal conditions during magmatism; occurrences in meta- morphic or sedimentary rocks are rare. Figure 1 illustrates the distribu- Fig. 1. — Index map of zeolite occurrences in Romania. 1. hydrother- mal in igneous rocks ; 2, open hydrologic system ; 3, burial diagene- tic — low grade metamorphic. Solid dots or triangles = zeolite samples cheinically analysed. 3 B cdel ea n I. (1972) Zeolipi din Muncii Apuseni și fenomenul de zeolitizare. Thesis of Doetor’s degree, Univ. “Babeș-Bolyai” Cluj. Institutul Geological României 3 THE NATURE AND COMPOSITION OF ROMANIAN ZEOLITES 145 tion of zeolite minerals in Remania. One can notice the frequency of the occurrences in Transylvania and especially in the Apuseni Mountains, while in other regions zeolite minerals are rarely found. Taking into consideration the geologic setting of the diverse zeolitic deposits we can adopt the following classification of Romanian zeolite occurrences : — hydrothermal zeolites in igneous rocks, — open hydrologic system type zeolite deposits, and — burial diagenetic — low grade metamorphic zeolites. Hydrothermal Zeolites in Igneous Rocks More than 150 zeolite occurrences of this type have been reported and practically all mineral species described so far come from such depo- sits, namely : natrolite, mesolite, scolecite, mordenite, heulandite, clinop- tilolite, stilbite, stellerite (epistilbite), chabazite, analcimeas well as the following intimately associated allied minerals : apophyllite, okenite and gyrolite recently discovered near Brad in the Apuseni Mountains by the author. All these minerals are of scientific interest but are not important from the economic point of view. They formed by precipitation from hot springs aud hydrothermal Solutions connected with shallow intrusions, vent areas of volcanoes, or lava flows, of three Alpine petrographic pro- vinces : 1) Mesozoic ophiolite formation of the Apuseni Mountains, 2) Early Tertiary banatitic volcano-plutonic complexes of the Apuseni Mountains and the Banat, and 3) Neogene volcanics of the Metaliferi Mountains, Maramureș, and the Călimani-Harghita volcanic chain. Very rarely are to be found zeolites genetically related to the Paleozoic eruptive complexes of the Highiș Mountains (natrolite, stilbite) or of luți- P1 avișevița in the Banat (natrolite, mesolite). The mode of zeolite occurrences in igneous rocks is as follows : a) cavity fillings, amygdules, veins or in the groundmass, b) replacement product of feldspars, especially plagioclases, c) pseudomorphs after volca- nic glass of Neogene tuffs and lavas and of banatitic ignimbrite rhvolites, and d) hydrothermal deposition in calcic skarn formations associated with banatitic intrusions. We have to emphasize the close associatton of sodic or sodocalcic low-silica zeolites (natrolite, scolecite or analcime) with low-silica lavas (basalts, spilites or andesite-basalts) in the Metaliferi Mountains, while in relation with Neogene silicic tuffs and lava, silica-rich zeolites, clinopti- lolite or mordenite appear. Examples are ignimbrite rhyolites of Ciceu-Dej and Gurasada, where vitric material is pseudomorphed by the mentioned zeolites. Exceptions to this generalization are scoleeites identified in ealcic skarns at the contact of the banatitic monzodioritic stock of Valea Seacă and of the monzogranite laccolith south-west of Stîna de Vale, Bihor, as well as in the Senonian breccia of the Vlădeasa Massif. In each of these shuatins the controlling influence may have been the carbona- tic geochemical environment and calcium-rich hydrothermal Solutions generated by banatitic calc-alkaline magma (I s t r a t e and Alexan- drina M e d e ș a n , 1977 ; Ist rate et al., 1980). Institutul Geological României igr/ 146 G. ISTRATE 4 Open Jlydrologic System Type Zeolite Deposits Although the occurrences of this type are not as varied mineralo- gically as the former, they are of considerable economic significance. Large masses of Neogene tuffs, the so called “Dej tuff”, are to be found in the Transylvanian Basin and in the Precarpathian zone. These tuffs are commonly several tens of meters thick and canbe traced laterali y for several tens of kilometers. They have been used for hundreds of years as building stone. The recent discovery of a rather high zeolite content of some of these tuffs lead to detailed investigations of these occurrences as well as their varied utilizations. Thin section study coupled with X-ray diffraction data have been essential for the identification of clinoptilolite, and sometimes of mordenite (author's data), in large proportions, as in the tuff occurrences of Perșani, Mirșid (P o p e s c u and A s v a d u r o v, 1978), Deva, Hărțăgani, Racoș, Zalău and Bistrița zones. In these rocks zeolites formed during diagenesis by the reaction of vitric rhyolitic mate- rial with interstitial and percolating water of meteoric origin in so called “open hydrologic Systems” (Sheppard, 1976 ; H a y , 1977). On the other hand in Transylvania and Prahova there exist many occurrences of varied tuffs and pyroclastic formations of Badenian, Sar- matian and Pliocene age, spatially associated with saline deposits, offer- ring in this way favourable conditions of zeolite formation in closed hydro- logic system. Burial Diagenetic — Dow Grade Metamorphic Zeolites Because it is difficult to distinguish obviously between these types, we only mention some occurrences, as follows : veins and cavity fiUings of stilbite in Carboniferous tuffs and sandstones of the Carapelit Formation in Dobrogea and laumontite and stilbite in Upper Cretaceous sandstones in the Rîmeț Valley in the South-Eastern Apuseni Mountains. In epimeta- morphic terrains of the Northern Apuseni (Drăganului-Zimbrului valleys) occurs laumontite ; the same mineral forms veins in amphibolites at Sadu in the South Carpathians (Zepharovich, 1859). Chabazite and stilbite near Muncelu Mic in the Poiana Rusca Mountains appear in geo- des and other cavities in a base metal ore deposit (Eădulescu and Dimitrescu, 1966). Chemical Composition of Romanian Zeolites So far there have been reported almost 35 chemical analyses on monomineral samples of Romanian zeolites, 14 of them belonging to the author (Tab. 1). For the purpose of characterizing the mineral species on the basis of their chemistry and detecting possible deviation from “normal” composition as well as variations in SiO2/Al2O3 and bivalent/ monovalent cation ratio, one may use the following diagrams : H2O — — SiO2—(Ca, Na2)O (Fig.2); CaO(MgO)—Na2O—K2O (Fig. 3) and SiO2 - A12O3 - CaO (Na2O, K2O) (Fig. 4.). Institutul Geological României THE NATURE AND COMPOSITION OF ROMANI AN ZEOLITES 147 TABLE 1 Chemical composition of Romanian. zeolites (wet Chemical analyses, weight %); cange of oxide values shoum for multiple analyses* SiO2 A12O3 CaO Na 2 O k2o II2O Natrolite 47 .07 27 .15 0 .67 14.78 0 .48 10.18 Mesolite (6) 45 .35— 24 .98- 8 .82- 5.09- 0 .05- 11 .56- 45 .97 26 .90 8 .95 6 .75 0 .15 16 .69 Scolecite 46 .05 26 .31 13 .33 0.21 0.00 14 .23 Stilbite 53 .05- 12 .19- 7 .17- 0.49- 0 .15 — 14 .07- (11) 69 .32 17 .40 8.82 1 .25 0 .43 19 .92 Heulandite 57 .77- 14.24- 4.59- 0 .75- 0 .30- 13 .89- (6) 61 .40 16.70 8.56 1 .16 1 .55 15 .21 Clinoptilolite 68 .10- 11.00- 2.44- 0 .29- 3 .25- 11 .36- (2) 69 .43 11 .80 1 .66 0 .39 3.35 11 .42 Lamnontite 47 .10- 19 .82- 10 .40- 0 .00- 0.00- 11 .02- (6) 57 .21 11.52 14.10 1 .60 0 .65 15 .42 Mordenite 69 .55 12 .50 4 .04 3 .00 0.00 10 .08 Chabazite 52 .09 16 .92 8.58 2.20 0 .55 19 .23 14 analyses ; other data = * Number of analyses shown in paranthesis ; author’s data = = 21 analyses. Fig. 2. — 2H2O - (Ca, Na21O — 2SiOa plot of composition of Romanian zeolites. 1, stilbite • 2, heulandite- 3, clinoptilolîte ; 4, laumontite : 5 cha- bazite ; 6, natrolite; 7, mesolite ; 8, scolecite; 9, mordenite. Institutul Geological României 148 G. ISTRATE 6 Ca O (Mg 0) Fig. 3. — CaO(MgO) — Na2O — K2O diagram. Only author’s analyses are plotted. See legend of Fig. 2. Fig. 4. — SiO2 — A12O2 — CaO(Na2O,K2) diagram. 1. stilbite; 2, heulandite; 3, laumontite; 4, chabazite; 5, natro- lite ; 6, mesolite ; 7, scolecite ; 8, inordenite. Institutul Geologic al României 7 THE NATURE AND COMPOSITION OF ROMANIAN ZEOLITES 149 Within Figure 2, “a”, “b” and “c” domains of oversaturated, normal and silica-undersaturated zeolites, almost parallel to the H2O —SiO2 side can be recognized; Figure 3 allows the obvious separaton of zeolites according to their main cation content. The diagram of Figure 4 exhibits the linear distribution towards silica-rich members, as foliows : mesolite, scolecite-laumontite-chabazite-stilbite-heulandite-mordenite. To the right- the values of SiO2 (weight per cent) are indicated. Preliminary Information concerning the trace element content in zeolites have recently been presented by Istrate et al. (1980). There have been analysed 14 monomineral samples by emission spectroscopy. The following elements have been determined : Sr, Ba, Ge, Be, Ag, Mn, Ti, V, Cr, Ni, Co, Ga, Pb and Cu. The samples studied are : 6 stilbites from Neogene volcanics, banatites and Mesozoic ophiolites, 2 heulandites from ophiolites, 3 laumontites from Neogene and banatitic magmatites, 2 clinoptilolites, 1 scolecite from banatites, 1 natrolite and 1 mesolite from ophiolites of the Metaliferi Mountains. Some interesting conclusions may be drawn from the data given in Table 2. B, Ge, Be Ag, Ti, V, Ga, Ni and Co appear in very low contents, generally below the spectral determination limit, with some few excep- tions. It is worth mentioning the fact that the Vlădeasa scolecite has a Be content of 15.5 ppm contrasting with the values < 1 of all the other samples, as well as the higher content of 15 ppm of the laumontite of the same region. The close examination of the Sr and Ba variation reveals that the highest contents are present in the lamellar zeolites, stilbite and heulan- dite exhibiting values much higher than the prismatic ones (mesolite, scolecite, laumontite). The two analysed heulandite samples contam more than 3,000 ppm Sr and over 1 per cent Ba. Their presence in the heulandite network being a rule rather than an exeeption. Deer et al. (1963) mention this possibility for the heulandite, whose K2O content is also a little higher exceeding even the Na2O one as in this case with K2O = 1.25 per cent and Na2O = 0.75 per cent, respectively. We shall mention that similar high values have been found in the case of heulan- dites genetically associated with the basic rocks of the Siberian traps (R i a b o v and Korne va , 1976). Future researches should have in view wliether it represents a peculiar feature of the chemistry of the Meta- liferi Mountains ophiolites or it is present in other petrographic provinces in the oountry, as well. At present, we mention that the same heulandite samples show the highest Mn contents as well pointing to the mineral high sensitivity and capacity for varied isomorphic substitutions. The distribution of gallium in the studied zeolites is also interesting to note. There exists an obvious tendency of this element to participate in the netw’ork of those zeolites with a prismatic habit (values of 30—50 ppm), while lamellar zeolites, namely stilbite and heulandite, usually exhibit contents ten times smaller (2—3 ppm). For a good explanation one should analyse the nature and dimensions of the free spaces in the 3a Institutul Geological României igr/ TABLE 2 Trace element content of magmatogene zcolites Cu 10 iq iq 10 10 iq iq o i> o co 01 oi 0 1.0^ oi r* o o T-« CO 01 rH 00 T-i Pb 10 0 10 10 Ol Ol * * * O CO 01 01 CO v/ \/ Ol 10 10 CO >O V V w v v V Ga 10 10 10 10 CO Ol 10 Ol Ol Ol Ol CO Ol o 10 'H TH CO CO Ol O Q Ol Ol Ol Ol 04 Ol 04 01 01 04 Ol Ol Ol Ol vvvvvvvvvvvvvv Ni 10 • Ol Ol Ol 04 Ol 04 Ol co Ol Ol Ol \/ Ol Ol Ol V V V V V V W v V VV O G 6 6 7 5 6 5 5 5 .5 6 5 4.5 5 5 > co co co co co co co co co co co co co vvvvvvvvvvvvvv 4 3 19.5 <3 15 <3 7.5 <3 5 4 .5 10 .5 14 <3 Mn 34 .5 56 58 5 .5 31 20 165 150 18 6 20 48 .5 21 36 Ag v V V V V V V v-v V V vv Be 10 V V V V V V V VVV V V Ge co co co co co co co co co co co co coco vvvvvvvvvvvvvv CQ o o o o o o o ooo o o oo co co co co co co co co co co co co co co vvvvvvvvvvvvvv Ba 17 10 .5 15 10.5 35 8.5, >1% >1% 13 .5 10 .5 18 10 .5 11 8 w O 10 CO 10 O 10 O O 00 O >0 co 10 CC O 7-1 • oo o o O CO «O O ^Ol T-I 10 co O O 01 01 01 co co A A Mineral; Locality 3 .J< J. " 2 « s £ w «> 2 — ® — ® 3 S « s 7S 3 > £ > > S - « g 2 « 2 £ 3 « « - - - s 5 § « S S * § « 5 S 5 S * £ •” ’S ° * 3 « 3 3 2 £ Cu S 2 yy§i0M o* a -c -a x: -a « x>« xs . jq • ■3 _ b S 5 5 5 $ S — 5>>S>S3wgS3w3K£X£1JJJS3SS2w tHOICO^iOCOOOO O O Institutul Geological României ■9 THE NATURE AND COMPOSITION OF ROMANIAN ZEOMTES 151 crystalline network of these minerals. Gallium, an element with a rela- tively small atomic radius (r.a. = 0.65), may be filtered by lamellar zeoli- ted and retained within the small channels of primsatic-fibrous zeolites The situation is reversed in the case of Sr (r.a. = 1.16) and Ba (r.a. = 1.43) cations which are preferentially retained within the network of lamellar zeolites. These facts could be of practicai interest in using zeolites as ion exchangers, which is the main characteristic of these minerals. The analysis of occurrences, mineralogy and chemistry of the Roma- nian zeolites leads to the following conclusions : Magmatogene zeolites are genetically associated with volcanic or intrusive bodies of the three main Alpine petrographic provinces : Meso- zoic ophiolites, banatites (Laramian magmatites) and Neogene volcanies. Sodic or sodo-calcic zeolites (natrolites, mesolite, heulandite and morde- nite) are associated with Mesozoic ophiolites, while calco-sodic zeolites (laumontite, stilbite, scolecite) associate, as post-magmatic hydrothermal products,, with the banatites and the subsequent Neogene volcanies. Scolecite, the most calcic mineral of this group occurs either as a late hydrothermal phase, filling the joints of Neogene andesites of Rodna, in the calcic skarns of Valea Seacă and Budureasa, or in Senonian calcareous breccias in the Vlădeasa Massif. Badenian volcanic tuffs contain frequently clinoptilolite, a zeolite structurally resembling heulandite in which (Na-(-K) > Ca and morde- nite, both originating in the devitrification of rhyolitic volcanic glass by the reaction with the infiltration meteoric waters in open hydrologic System. In view of an accurate diagnosisof different minerals of the zeolite group, a complex physico-chemical study is necessary (chemical and optical analyses, X-ray diffraction, thermo-differential analyses, infrared spectroscopy, scanning electronic microscopy). On the basis of chemical data, we may trace, on the proposed diagrams, the domains characteristic of different zeolites thus designa- ting the mineral species (diagrams Ca(Mg)O-Na2O—K2O; SiO2 —A12O3— -CaO, (Na2O, K2O) and SiO2-H2O-(Ca,Na2O.). The trace element contents of zeolites are generally very low. The highest Ba and Sr contents occur in heulandites and stilbites, while Ga contents are very low in these minerals, this element concentrating in prismatic-fibrous zeolites (natrolite-mesolite-scolecite group, laumontite, ete.). Zeolite occurrence and their sequence of deposition are controlled by their forming energy, water content (zeolitic water) and of the Al/Si ratio; zeolites with higher forming energy, less hydrated and with a higher Al/Si ratio will crystallize first. In Romania further investigations of new zeolite occurrences, of their mineralogy, composition and mode of formation, as well as studies of their utilization are needed. Special interest will be focused upon the Identification of zeolite deposits in open and closed hydrologic systems. Institutul Geological României 152 G. ISTRATE 10 REFERENCES Ackner M. J. (1955) Mineralogie Siebenburgens mit geognostischen Andeuteungen, Stein- hausser, Hermannstadt. Borcoș M. (1960) Contribuții la studiul zeoliților: magneziolaumontitul de la Musariu. ' Stud. cerc. geol. geofiz. geogr., seria Geol-, 5, 4, București. Deer W. A., Howie R. A., Zussman J. (1963) Rock Forming Minerals. 1.4, Long- mans, London. G i u ș c ă D. (1945) Un nouveau gisement de zeolites dans les Monts du Bihor. C. R. Acad. Sci., 8, București. H a y L. R- (1977) Geology of Zeolites in Sedimentary Rocks. In : Mineralogy and Geology of Natural Zeolites, Mumpton Ed., 4, 53 — 64, Blacksburg, Va. Ist rate G. (1980) First Mordenite Occurrence in România. Rev. Rotim. Geol. Geophys. 1 Giogr., serie de Geol. 24, București. — Medeșan Alexandrina (1977) Zeolites from the Vlădeasa Massif. Rev. Rotim. Geol. Gcphys-, Geogr., sirie Geol., 21, 35—44, Bcurești. — Medeșan Alexandrina, Zâmircă A 11 a (1980) Contribuții la cunoașterea chimismului zeoliților magmatogeni din Munții Apuseni. D. S. Inst. geol. geofiz., LXVI/1, București (in press). K r ă u t n e r H. G., Medeșan Al e x a n d r i n a (1966) Metalaumontitul de la Ruschița, Stud. cerc, geol., geofiz. geogr., seria Geol. 11, 1, 183—'89, București. Popescu Florică, Asvad rov H. 11978) La cliuoptilolite dans les tufs de Transyl- vanie. Stud. tehn. econ., ser. 7/14, 131 — 142, București. Răduleseu D., Dimitrescu R. (1966) Mineralogia topografică a României. Edit. Acad. R.S.R., București. R i a b o v V. V.. K o r n e v a T. A. (1976) O țeolitah noriliskovo raiona (Severo-Zapad Sibirs- koi platformî). Trudi Inst. Geol. Gheofiz., 263, Nauka, Novosibirsk. Sheppard A. R. (1976) Zeolites in Sedimentary Deposits of the Northwestern United States — Potențial Industrial Minerals. Montana Dur. Mines and Geology, Spec. Publ., 74, 69-84, Kalispell. Z e p b a r o v i c h V. R. (1859) Mineralogisches Lexicon des Kaiserthums Osterreich, Brau- muller, Wien. \ I6R.> Institutul Geologic al României NATIVE TELLURIUM AND TELLURIDES MINERALIZATION FROM MUSARIU, BRAD REGION (METALIFERI MOUNTAINS), ROMANIA1 BY ION BERBELEAC2 Native tellurium. Tellurides. Native gold. Sulphosalls. Quartz andesites. Diorites. Metal- logenesis. Neogene volcanism. Subvolcanic rocks; Apuseni Mountains-Neogene eruptive- Brad-Săcărimb sector. Sommaire M i n e r a 1 i s a t i o n s d e tellure natif et t e 11 u r u r e s de Mu s a r 1 u, de la region de Brad (M o n t s Mit a l li t Jr es) - R ou ma nie. Le corps subvolcanique, constitui d’andesites quartziferes et diorites quartziferes sarmatien-panno- niennes (?), contient dans sa pârtie superieure des mineralisations filonniennes d’or natif, tellure natif et tellurures d’or et argent et, en profondeur, des mineralisations de dissemi- nation cuprifere. Les mineralisations de tellure et tellurures d’or et argent, inconnues jusqu’ă present, apparaissent dans deux nionnets situ6s dans les andesites quartziferes intensement argilisees et sericitisies. Le tellure natif fonne des aggregats pannidiomorphiques et allotrio- morphiques fins et grossiers (0,1—3 cm) de couleur blanche-etain, avec eclat tnetallique prononei. Les formes observeeș sont: in [1010], RțlOÎl] et r[01îl]. D = 6,02—6,16 g/cm3 Les valeurs de la micro-durete (VHN 10_20) varient de 29 ă 74 kg/mm2. Les proprietis opti- ques principales soni : couleur blanche â nuances cremes ; anisotropie (gris-blanche) pronon- cec et reflectance (%) = 63,46 (486), 63,29 (551), 62,48 (589), 59,17 (656) en air, et 56,64 (486), 56,58 (551), 55,0 (589), 54,32 (656) en immersion. L’analyse chimiquc de deux mostres a donne 99,45% et 96,93% Te. Les lignes de diffraction principales risulties des donnees obtenues par l’analyse â rayons X sont : 3,23 (100) 2,35 (37), 2,25 (33), 1,824 (20), 3,853 (16), 1,615 (11), 2,083 (10) et 1,475 (10). Le tellure natif du filonnet no 1 s’associe aux te- lurures et bisulphures qui occupent generalement la pârtie marginale de celui-ci. Les tellurures connus sont : frohbergite, nagyagite, calavcrile, krennârite, sylvanite, petzite, hessite, empres- sile ct altaîte. Parmi les sulphures, nous mentionnons la pyrite, la chalcopyrite et la blonde. 1 Paper received on April 7, 1980 and accepted for publication on April 8, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București 32. Institutul Geological României 154 I. BERBELEAC Le rutile et la chalcosine apparaissent sporadiquement, tandis que le tcllurite est relativemcnt frCquent. La succession de mineralisation a eu l’âvolution suivante : sulphures communes- tellure natif-tellurures d’or et argent. La succession de l’or natif dans le gisement a et6 celle- mentionnâe ci-dessus. Les quantit6s appreciables de tellure dans les filonnets â cote des tel- lurures et sulphures (2 — 3%) menenl ă la conclusion que la mineralisation d6crite consiste premidrement en tellure. Cclle-ci appartient au type subvolcanique jeune ». Iniroduction The main occurrences of native tellurium and tellurides from Roma- nia belong to the Neogene metallogenic periods and are restricted, espe- cially, to the Metaliferi Mountains area. In this part of the Apuseni Mountains, the most characteristic occurrences of native tellurium and gold and silver tellurides are to be found in six old mining centers : Săcărîmb, Fața Băii, Botes, Stănija, Ruda-Barza and Baia de Arieș (G h i ț u 1 e s c u , Soc o le seu 1941, Ian o vi ci et al., 1969). From all these centers, Săcărîmb is the most famous. Here, for the first time in the world, nagyagite and sylvanite were found and described (Dana and Dana, 1961). Details concerning the native tellurium and gold and silver tellurides are given by numerous authors (M ii 11 e r , 1784, K a 1 p r o t h , 1802 and P e t z , 1842 in V1 a s o v , 1966 ; L o c z a , 1890, in Dana and Dana, 1961; B e r w e r t h , 1917, in E ădu 1 e s cu and D i in i- t r e s cu , 1966 ; He I k e , 1934 ; Giușcă, 1935, 1936 ; I a n o v i c i et al., 1969, 1976; Ramdohr and Udubașa, 1973). As far as the native tellurium and tellurides occurrence from Musariu is concerned, we underline the fact that it was unknown. Geolog y Musariu area lies in the vicinity of the Brad town, in the central part of the Metaliferi Mountains. In this area there is an important Neogene structure which comprises the native gold deposit of Musariu. The broad area of Musariu deposit is built up of Mesozoic and Cenozoic formations of sedimentary and volcanic origin (Fig. 1 a, d). Mesozoic formations are represented by Upper Jurassic and Lower Cretaceous volcanic rocks (andesites, basalts, ete.). These rocks are overlain by a Neogene sedimentary-volcanic pile which consists of conglomerates, marls, argillites, sandstones, tuffites, tuffs, lavas and pyroclastic quartz andesitic rocks (Fig. 1 a,d). AII these rocks are intruded by quartz andesites and quartz diorite porphyry rocks which form the so-called Musariu subvol- canic body (Ian o vi ci et al., 1969, 1976, 1978, Bor coș et al., 19783, 19794, 19805). The rocks of this body belong to the Neogene facies of Plutonic rocks of the Metaliferi Mountains. The quartz diorite-porphyry 3. 4. 5 Unpublished reports, Arch, IGG, București. Institutul Geological României 3 TELI.URIUM AND TELLURIDES FROM MUSARIU 155 Fig. 1. — Geological sketch map of Musariu Area (a), the linei level in Musariu mine (b), detail on veinlet no 2 (c) and cross-section through Musariu volcanic body (d) (according to lanovici et al., 1909 ; Borcoș et al., 1979 ; unpublished data modified by the author.) 1, Mesozoic basic rocks; 2, Tertiary volcano-sedimentary pile ; 3, lavas and pyroclastic rocks ; 4. quartz andesites and quartz-diorite porphyry ; 5 : a, native gold veins; b, telluriumand telluride veinlets; 6, porphyry copper mineralization; 7: a, native gold vein at the Und level; b, tellurium and telluride veinlets : c, fracture with breccia filling; 8, outline of sub- volcanic body at about 500 m below the surface; 9, drillhole; 10, —20 m below the Und level; 11, pit. I. BERBELEAC rocks have a compact grain structure built up mainly of plagioelase and hornblende. We note the fact that these rocks are closely connected with the origin of porphyry copper deposit from Musariu as well as other parts of the Metaliferi Mountains. We remark that the native gold (G h i - țulescu, Socolescu, 1941; lanovici et al., 1969, 1977) native tellurium and telluride mineralizations are also genetically and spatially associated with the subvolcanic body. In this body and round it, the products of hydrothermal and metallogenetic activity show a typical zonality : a large argillic-sericitic + adulai* envelope with native gold and tellurium and tellurides mineralization lies in the upper part of the intrusion, while in the depth, the potassic and propylitic alteration and porphyry copper mineralization do occur (Bor coș et al., 1979®, 1980’). Native Tellurium and Tellurides Veinlets The native tellurium and tellurides described here were found within two veinlets (no.l and no. 2, Fig. 1 b) situated in the neigh- bourhood of a native gold vein (no. 44). These veinlets seem to be cros- sed by native gold veins (Fig. 1 c). They strike in the same directions (NW-SE) and occur at about 20 m below the second level from Musariu mine (Fig. 1 b). The veinlets lie within white or grey white argillized quartz andesites and have, as a rule, reduced thickness (0.5—3 cm, excep- tionally 5 cm) and marginal bands and nets of clay minerals (caolinite). They have sharply defined walls and in their neighbourhood there are some tectonic dislocations (Fig. 1 c) with pyrite and without native gold and tellurium and tellurides. The main gangue minerals contained in the ore veins are quartz, caolinite and baryte. Ore minerals are represented by pyrite, sphalerite, chalcopyrite, rutile, native tellurium, frohbergite, sylvanite, calaverite, krennerite, nagyagite, petzite, empressite, hessite, tellurite and unidenti- fied tellurides. Within the veinlets the native tellurium and tellurides are volume- trically the most abundant ore minerals. As a rule, quartz is associated with native tellurium and tellurides, while the clay minerals contain pyrite. We note the fact that in the second level of Musariu mine, the clay minerals are predominant in native gold veins and thin and discon- tinuous bands of grey chalcedony or white-grey and fine-grained prisma- tic quartz aggregates are abundant in native tellurium and tellurides veinlets (Berbeleac, 1980). 6’ 7 Unpublished report s, Arch. 1GG, București Y Institutul Geologic al României 5 TELLURIUM AND TELLURIDES FROM MUSARIU 157 Of the two mentioned veinlets, veinlet no. 2 consists almost exclu- sively of native tellurium, while veinlet no.l contains, except for native tellurium which is also predominant, gold and silver tellurides and other tellurides. In the latter case, the native tellurium prevails in the inner part of the veinlet, whereas the tellurides and sulphides occur in the outer part. The ore’s structure is mostly massive. Less frequently impregnation, brecciated, drusy and cavernous textures are present. The examined ore samples consist largely of native tellurium with irregular concentrations of disseminated pyrite, minor chalcopyrite, tel- lurides (frohbergite, krennerite, calaverite, sylvanite, nagyagite, petzite, hessite, empressite, altaite, unidentified tellurides) and tellurite and traces of sphalerite, rutile and chalcocite. Tellurides were found in the majority of the examined samples proceeding from veinlet no. 1. The particles are mostly very fine-grained, generally less than 60 g; however in rare cases they attain about 300țj.. There wrere identified optical properties which are consistent with published data (V1 a s o v , 1966, U y t e n b o g a a r d t and Burke, 1971, Ramdohr, 1971). Deseription o£ Ore Minerals Native tellurium. Volumetrically, the native tellurium is the most important ore mineral of the veinlets. It is the only major ore consti- tuent which generally develops crystal faces. It forms visible monomi- neralic and partly mineralic fine or coarse-grained compact panidiomor- phic, hipidiomorphic and allotrimorphic aggregates. The aggregate outli- lines are, as a rule, intensively zig-zagging. The internai geometry is dicta- ted by the fact that when the native tellurium meets native tellurium, the competition between the individuals leads to a more or less coarse ore equigranular texture. The visible individual grains of the coarse-grained aggregates often reach 1—2 cm and excepționaliy 3 cm in length; usually many visible grains fall in the range from 2—3 mm to 5 mm in length (Berbeleac and D a vid, 1980). The same large crystals were found in Zlatna- Almașu Mare (Eomania) Kawatsu and Tein regions (Japan) and John Joy mine (Colorado) (V1 a s o v , 1966). Native tellurium individuals contained in the same volume and of comparable size may show varia- ble shape and perfections which again may suggest the presence of more than one generation of the mineral. Some excepțional and volumetrically important prismatic crystals are found as nets in the central part of veinlets. Here it has grown in vug-like voids together with quartz. Some of these larger individuals conserve the best development of plane crystal faces flattened parallel to [1010], sometimes with rounded edges. On the fresh surface the native tellurium has a tin-white colour and a brilliant metallic lustre ; after a lapse of time they become blue and Institutul Geologic al României 158 I. BERBHIiEAC 6 then grey with black tints. Many surfaces of the coarse-grains often conserve the traces of the perfect (1010) and imperfect (0001) cleavage planes and some of them show the step-like and plane-choncoidale frac- tures. We note the forms m {1010}, R{1011} andr {0111}. The euhedral crystals with these forms are more frequently in the central part of vein- lets and usually within old vug-like voids. They remind those recognized by L o c z a (1890, in Dana and Dana, 1961) in Fața Băii area and Kawatsu and Tein mine (Japan, Watanabe, 1960). The va- lues of microindentation hardness (VHNlo_2o) range between 29 — —76 kg/mm2 (Berbeleac and D a v i d , 1980). These values are in agreement with the data of V1 a s o v (1966) and Uytenbogaardt and B u r k e (1971). The hardness of native tellurium is low and smaller than that of calaverite, krennerite, empressite, petzite, hessite and froh- bergite and greater than that of sylvanite and altaite. The density tests of tellurium from Musariu range between 6.02 — 6.18 g/cm3 (Berbe- leac and D a v i d , 1980). In reflected light, tellurium is white with creamy hue and against some tellurides it appears as follows : white more lighter than hessite, empressite, krennerite and calaverite; white creamy less bright than altaite and less white-creamy tints than svlvanite. The reflectivity values — - 63.46% (486); 63.29 % (551); 62.48% (589), 59.17 % (656) in air and 56.64 % (486), 56.58% (551), 55% (589) and 54.32 (656) in oii — agree with literaturo data (F o 1 i n s b e e , 1949, R a m d o h r , 1975). Double reflection of native tellurium is slight and more visible at the grain boun- daries (O = white to grey-white and E = brown grey). Fairly polished, some grains show two directions of cleavage and often irregular, rarely regular triangular splintering (Fig. 2 in, Pl. I, Fig. 1). The anisotropy of native tellurium is strong but with no pronounced colour effects : grey with bluish and brownish tints. One remarks also a weak anomaly of anisotropy and many cases in which the individuals of panidiomorphic aggregates show euhedral forms, sometimes with rounded edges (Fig. 2 b,c). In the polished sections, two morphostructural types of native tellurium are distinguished : a) euhedral to subhedral crystal aggregates and anhedral grain aggregates deposited after the sulphides and before the tellurides (Fig. 2, Pl. I, II) and b) drops and minute inclusions within the tellurides (Fig. 2 a-e, Pl. II, Fig. 3). The first type is very common and gives the complexity of textural and structural features. In monomineral aggregates the internai geometry of the grains shows frequently an inequigranular text urc, while the outline in polymineral aggregates is controlled by stronger minerals (pyrite, chalcopyrite, quartz, etc.). As concerns the intergrowth and replacement zone the native tellu- rium develops a convex outline with concave splashes and cuspate ten- tacles (Fig. 2). These zones are recognized by many swarms of rounded inclusions, frequently pyrite, chalcopyrite and quartz (Fig. 2, Pl. I, Fig. 2) and by complex and interpenetrating textures. However the study of ore minerals of the two veinlets from Musariu mine shows the < \ Institutul Geological României TELLURIUM AND TELLURIDES FROM MUSARIU 159 Fig. 2. — Relationship between the ore and gangue minerals in tellurium and telluridc vein- lets from Musariu. 1, pyrite; 2, chalcopyrite; 3, rutile; 4, tellurium ; 5, tellurium with tellurite ; 6, frohbergite; 7. sylvanite; 8,krennerite 9, petzite; 10, hessite; 11, empressite ; 12, altaite ; 13, unidenti- fied telluride; 14, quartz. In black irregular pits. Institutul Geological României 160 I. BERBELEAC 8 complex relationship of minerals from which we find out that tellurides have penetrated, replaced and cemented tellurium (Fig. 2, Pl. I, II). Taking all these into considerat ion, it results that the sequence of minerali- zations in the two veinlets from Musariu mine, began with common sul- phides, continued with native tellurium and finished with tellurides. These observations change the previous data (Berbeleac and D a v i d, 1980) which placed tellurium after gold tellurides. According to Berbeleac and D a v i d (1980) the Chemical composition of native tellurium (99.45% Te and 96.93% Te) is com- parable with literature data. In their study, the above mentioned authors gave also the results of X-ray data (Table). These results are similar to those given by the ASTM Gard. Frohbergite —FeTe2. Frohbergite was identified in veinlet no. 1. It appears as fine-grained friuges around chalcopyrite (Fig. 2 a). The colour of frohbergite is pinkish-lilac; a light reflection pleochroism from pinkish- lilac to lilac-grey and moderate anisotropy with colour ranging from purple-red to orange-red and ink-blue were observed. The relative relief of frohbergite is higher than that of tellurium and chalcopyrite. The in- clusions in frohbergite are first the chalcopyrite and tellurium. Pyrite and gangue minerals are also important. The intergrowth with chalcopy- rite and tellurium is intimate and shows deep replacements with frequent concave embayments (Fig. 2 a). According to microscopic study the frohbergite seems to be the first telluride deposited from the tellurides sequences. It was found in associations with tellurium, chalcopyrite, chalcocite pyrite, sphalerite, sylvanite, calaverite, krennerite, petzite and tellurium. These associations are generally, the same associations which w’ere found at Robb Montbray mine, Quebec (V 1 a s o v, 1966) and Sâcărîmb, Romania (R a m d o h r and U d u b a ș a, 1971). Sylvanite — AuAgTe4. It is an important constituent of the ore. I-Iowever its relative and absolute quantity is highly variable from place to place. The sylvanite,as well as other tellurides are present as thin sub- millimetrical fissures within tellurium. Frequently it also appears to be an intergranular filling between tellurium crystal faees. Larger areas of sylvanite are apparent only on the boundary of tellurium and sul- phides, pyrite especially (Fig. 2 f). In detail sylvanite exhibits usually fine-grained allotriomorphie and hipidiomorphic aggregates. Within the aggregates the crystal faces are seen as exceptions. They consist of mul- tiple anhedral individuala of highly variable grain size: 20 —150 g. The majority, probably have a size range of 30—50 fi- la transmitted light the colour of sylvanite is cream-white and against tellurium it appears cream-brown. The reflection pleochroism is highly distinct, both with and without oii,and especially along the boun- daries of grains and twin lamellae : bright cream-white to darker cream- white brown in air and light-cream-white and creamish-brown in oii. The anisotropy is very strong with a pronounced double reflection colour vigr/ Institutul Geological României X-ray powder data for native tellurium 'A Institutul Geologic al României igr/ 162 I. BERBELEAC 10 effect: from distinctly pinkish-white to greyish-brown ■with brownish- yellowish and bluish tints. A very important identifying feature of syl- vanite is the lamellar twinning, visible, in general, with crossed nicols (Fig. 2 e, f, g, h, i, Pl. I, Fig. 3, 4). The twinning parallel to (100) and cleavage often well pronounced, usually II (010) were used also for its identification. The relative relief is lower than that of native tellurium, hessite, altaite. Sylvanite includes within its aggregates pyrite, chalco- pyrite, native tellurium, nagyagite and quartz. Occasionally, inclusions of pyrite have been observed as inequidimensional fine rounded or ragged grains. The outstanding textural features of sylvanite consist in a variety of intergrowths of tellurium, petzite, hessite unidentified tellurides. Under the microscope these relationships aid to specify the special ratios among the sylvanite, other telluride and gangue minerals which can be presu- med as follows : a) sylvanites penetrate the grain boundaries of sulphides and native tellurium; b) sylvanite seems to be penetrated by calaverite, krennerite, petzite, hessite and a telluride with mirmekitic texture and c) sylvanite is probably partially contemporaneous with nagyagite. Syl- vanite is usually associated with tellurium, krennerite, calaverite, nagya- gite, petzite, hessite and empressite. Calaverite — AuTe2. It is a minor constituent. Like krennerite it is frequently found in small areas along the sylvanite, native tellurium and sulphide grains. Sometimes it is seen in small bands situated between the sylvanite and tellurium grains and sulphide aggregates. The bands con- sist of irregular fine-grained aggregates and comprise many inclusions of pyrite, rutile, native tellurium and quartz. The aggregate grains show an anhedral habit and weak reflection pleochroism with yellowish-white and brighter yellowish-brown tints. Anisotropic effects are distinct with yellow-grey and grey-brown colours. In all these the colour is very similar. Krennerite — AuTe2. It is anhedral and consists of fine-grained aggregates. Krennerite was found in most samples from veinlet no 1 in quartz ore portions. It occurs as intergranular filling between native tellurium (Fig. 2 k, Pl. II, Fig. 1) and sylvanite (Fig. 2h). Larger areas between pyrite and sylvanite appear only on krennerite and calaverite. In this case, it is difficult to find the true genetical ratios bet- ween these minerals. A very different type of intergrowth is present in the above mentioned areas. These are represented by thin and someti- mes oriented krennerite and calaverite grains. Both minerals are in appro- ximately equal proportions and display complicated intergrowths. The relative relief of krennerite is higher than that of calaverite and sylvanite. We note also the weak reflection pleochroism and quite distinct anisotropy which are stronger than in calaverite. Nagyagite — Pb5Au (Te, Sb)4S5_8. Nagyagite occurs sporadically over a great part of the total ore volume. It was noticed especially as inclusions of thin, tabular, isolated crystals or fine-grained aggregates in \ Institutul Geologic al României 11 TELLURIUM AND TELLURIDES FROM MUSARIU 163 sylvanite. It is important to underline the frequency in sylvanite of euhe- dral crystals of nagyagite (Pl. I, Fig. 4). Frequently, nagyagite appears to be an intergranular filling between sylvanite (Fig. 2e) and tellurium grains (Fig. 2n). In polished sections the colour of nagyagite is grey. The weak reflection pleochroism and anisotropy (yellow-grey, grey-blue and dark brown) were the main diagnosis criteria. In all the known cases there are no inclusions in sylvanite grains. We remark also the association of nagyagite with sylvanite, native tellurium and rarely with calaverite and krennerite. Petzite — Ag3AuTe2. It is a minor ore constituent. Petzite was frequently found on the border between sylvanite and tellurium grains. Sometimes, petzite and hessite fiii the fine fissures of the two mentioned minerals. Petzite forms small and fine-grained aggregates in which the crystal faces have never been seen. The reflectivity of petzite is moderate comparable with that of hessite. In contrast with this, against light white (in air) it has a pale lilac colour- and with crossed nicols it is isotropic. We remark the low relief, invariably lower than in the case of hessite, sylvanite and tellurium. Hessite — Ag2Te. Fine-grained aggregates of hessite have been met in association with sylvanite, tellurium, calaverite, krennerite petzite and an unidentified telluride. Hessite has been frequently identified as fine-grained aggregates in filled fissures where, as a rule, it is associated with an unidentified telluride (Fig. 2d, Pl. II, Fig. 2, 3). Sometimes, in contact zones of the two above mentioned minerals, among the obser- ved microtextures, the so-called sub-graphitic or pseudo-eutectic textures, seem to be the most common. This aspect is given by the mirmekitic textures between, probably, a gangue mineral and these two ore minerals. The reflection pleochorism (grey-white colour, in air and dull brownish- white to greyish-blue purplish, in oii) and quite distinct anisotropy with dark-orange and slate-blue, dark brownish-purple and light yellow in oii have been the principal criteria for diagnosis. Empressite — AgTe. It was found as fine-grained aggregates in thin fissures from tellurium (Fig. 2m, Pl. II, Fig. 4). Empressite and other similar tellurides are veining tellurium along plane grains. The reflectivity of empressite is moderate and its anisotropy and reflection pleochroism are distinctly too strong (white-greenish-yellow). Empressite is of yellow- grey colour with pale greenish tints. According to published data, empres- site has been detected in few deposits : Baia de Arieș (V1 a s o v, 1966) and Săcăiîmb (Schrauf, 1878; Thompson et al., 1951), Empress Josephine mine (V1 a s o v, 1966 ; Thompson et al., 1951), Red Cloud (Thompson et al., 1951), Kalgoorlic (Markha m, 1960) and in a certam gold ore deposit in Armenia (Vlasov, 1966). In Musariu mine, the empressite associates preferentially with tel- lurium and sylvanite. Altaite — PbTe. Altaite was found as very small, xenomorphic aggregates. It penetrates the border of native tellurium grains in vein form. Sometimes, in polished sections, altaite shows a cubic cleavage Institutul Geological României 161 I. BERBELEAC 12 with triangular pits (Fig. 2a, b). In contrast with tellurium, altaite has white colour, high reflectivity and is isotropic; like Pobb Montbray (V1 a s o v, 1966) it shows weak anisotropy. Unidentified Ore Minerals. A number of minerals of the investiga- ted specimens remained unidentified. From these we mention only two which seem to be tellurides. 1) A strongly pleochroic and anisotropic mineral was found in the specimens from veinlet no 2. It forms, almost exclusively, minute veinlets which penetrate the native tellurium (Fig. 2d, i, Pl. II, Fig. 3). It appears also as small allotriomoprhic aggregates between the boun- daries of native tellurium, sylvanite, calaverite, krennerite and hessite (Fig. 2d). The colour of pleochroism in air is ordinary grey (yellowish- grey to grey-yellowish) and the anisotropy colour (in air) ranges from white-yellow-brown to bluish-grey. The relative relief is lower than that of sylvanite, krennerite, calaverite, hessite and tellurium. It polishes easily and well, but shows substitution mirmekitic textures. It comprises almost always an interpenetrating growth of large mineral grains ■with very fine ones and apparently a gangue mineral (Pl. II, Fig. 2, 3). The grain boundary of this unidentified telluride with gangue mineral is very complicated; the intergrowths of these two minerals frequently have a vermicular texture. This fact resembles the “graphic granitic” textures in which the predominant component is probably a telluride. 2) Within sylvanite, calaverite, krennerite and native tellurium aggregates together with pyrite, quartz and other mineral inclusions, a prismatic isolated mineral was found. This mineral shows a perfect parallel extinction with darkest positions and grey-blue and blue colours. The relative relief is higher than tellurium, sylvanite and calaverite. Being described and partly well-known these minerals and others demand further study. Other Minerals. By investigating the ore minerals from two native tellurium and telluride veinlets, before the above mentioned minerals, pyrite, chalcopyrite, sphalerite and rutile do occur. From these, pyrite is volumetrically the most important. Most frequently, pyrite occurs as subhedral grains with individuals ranging from 20—30 p. to about 1—2 mm. The best developed crystal faces are usually in argillized andesites. Most frequently pyrite occurs as equidimensional but anhedral inclusions (Fig. 2, Pl. I, ÎI). Inclusions with outlines made up of crystal faces are rare. The inclusions of pyrite inside the native tellurium and tellurides are an example of “poikiîitic” texture (Fig. 2, Pl. I, II). Smaller inclusions of pyrite appear, as a rule, as rounded isolated grains or as a series of more or less rounded aggrega- tes lying in a tellurium or tellurides matrix (Fig. 2, Pl. I, II). The pyrite is corroded by chalcopyrite over large areas along grain boundaries where a vermicular intergrowth develops. Chalcopyrite occurs as patches of irregular size and distributions. It is associated -with pyrite, chalcocite, frohbergite, tellurium and tellurides. When chalcopyrite occurs as small inclusions, it has mostly adapted “rounded form”, as well. Institutul Geologic al României JCR/ 13 TELLURIUM AND TELLURIDES FROM MUSARIU 1C5 Inclusions in chalcopyrite are pyrite sphalerite and gangue minerals, especially quartz. Sphalerite is a minor constituent and is generally formed as fine inclusions, especially in tellurium and tellurides. Rutile has been identi- fied only occasionally. Tellurite — TeO2. In veinlet no 1, ncar the wall rock and in small geods, small acicular crystals or clusters and spherical masses showing radial structure have been identified. These minerals, associated with goethite, have yellowish-white colour and almandine lustre. In transmit- ted light, tellurite is transparent and biaxial positive. It is generally very scarce in some native tellurium aggregates where it forms thin and aci- cular crystals. (Fig. 2 a, h). Tellurite originates in the transformation of native tellurium. Chalcocite — Cu2S. It is probably a supergene mineral. It occurs mostly as thin rinds at the grain boundaries of chalcopyrite. In addition to this, replacement structures and replacement relics are characteristic. General Features of Mineral Assemblages The intergrowths of opaque minerals and of opaque minerals with gangue minerals and the apparent successions of minerals are identical for all the șpecimens. As concerns textural and structural relationships of opaque to non- opaque minerals, three different mineral assemblages may be distinguis- hed, each of them being associated to the tellurides and sulphosalts stage of the Und metallogenetic phase from the Metaliferi Mountains (I a n ov i e i et al., 1969; B o r c o ș, Manii ici, 1965; Berbeleac, 1975). The three mineral assemblages present the following characteristics : 1. Assemblage I occurs in veinlet no 1. It is characterized by the predominance of pyrite. Copper is abundant in the form of chalcopyrite and chalcocite, the former dominating the latter. Sphalerite is rare. 2. Assemblage II occurs in both veinlets. Here, native tellurium seems to be the unique mineral. 3. Assemblage III forms the gold and silvei' tellurides in which syl- vanite is the dominant mineral. Frohbergite, calaverite, nagyagite, pet- zite are subordinate to krennerite and in places also to altaite, hessite and the mineral with mirmekitic texture, probably a telluride. The textural relationships of opaque and non-opaque minerals per- mitted to make the following general observations: alloreminerals con- tam inclusions of non-opaque minerals. Euhedi-al quartz inclusions (Pl. I, Fig. 2) appear within the assemblages II and III; the inclusions of tellu- rium and other tellurides are often with round or sharp outlines; euhedral crystals of ore minerals embedded in tellurides are represented by nagya- gite ; gold and silver tellurides appear frequently as an infilling between sulphide grains and native tellurium. 166 I. BERBDJJEAC 14 The observed textures were sorted into the following three groups : a) proper granular textures; b) mirmekitic textures (Pl. II, Fig. 2, 3) and c) textures resembling replacement ones (Fig. 2). Conelusions According to the present knowledge on the tellurium and tellurides mineralizations and the data in the preceding pages, the Musariu mine- ralization shows the following characteristics of its modes of occurrence : 1) It was formed in close genetical relations to quartz-andesitic and quartz-diorite porphyry, Tertiary subvolcanic activities in the late stage of metallic mineralizations from the Metaliferi Mountains. Tellu- rium and tellurides mineralization seem to have also taken place during the second stage (together with native gold) of a single metallogenic phase (Sarmatian-Pannonian, Ia no viei et al., 1976). This minerali- zation belongs to the “young” subvolcanic type (Vatukoula, Fiji Island, V1 a s o v, 1966) and can be compared with other important and similar occurrences in Romania (Săcărîmb, Fața Băii, Baia de Arieș, I a n o v i c i et al., 1976) and in the world (Kawatsu, Tein, John Joy, R a m d o h r, 1975; VI as o v, 1966). 2) Tellurium and tellurides mineralization consists of two small fissure-filling veins and occurs in Musariu mine at the same levels with native gold vein. These two types of mineralization appear in the upper part of the subvolcanic body, within a broad envelope of argillized rocks. We note also the fact that tellurium and tellurides from many typical hydrothermal mineral associations (tellurium-quartz; tellurium-altaite- quartz ; tellurium-sylvanite-calaverite; sylvanite-calaverite ; petzite-hes- site ; sylvanite-nagyagite-tellurium ; sylvanite-unidentified telluride, etc.) are in agreement with the phase diagram of the Au—Ag—Te ternary system (M a r k h a m, 1960). 3) Successive mineralization might have probably taken place according to the following order: pyrite-sphalerite-chalcopyrite-tellu- rium-frohbergite-gold and silver tellurides. At present, there are not sufficient data for estimating the real genetic relationships between the diverse tellurides on one hand, and these and native gold, on the other hand. We note the fact that in other places from the Metaliferi Mountains (Săcărîmb, Fața Băii, Fericeana, Boteș, Baia de Arieș, etc.) the native tellurium deposited only partially at the same time with gold and silver tellurides. It appears mostly after native tellurium and tellurides (H e 1 k e, 1934 ; Ghițulescu and S o c o 1 e s c u, 1941; I a n o v i c i et al., 1969; Bo r c o ș, Mani li ci, 1965). 4) The native tellurium and tellurides mineralization of Musariu mine consists mainly of tellurium; the tellurides (sylvanite, calaverite, krennerite, nagyagite, petzite, hessite, frohbergite and altaite) are present in minor amounts .As regards this aspect, it is a typical tellurium mi- neralization. Institutul Geological României 15 TELLURIUM AND TELLURIDES FROM MUSARIU 167 5) The source of mineralizations lies probably in parental magma, •while the later phase of metallogenetic activity might be responsible for the formation of tellurium and tellurides occurrences. Otherwise, the preliminary analysis of available Information has made possible the re- cognition of a metallogenic activity associated to island arc volcanism from the Metaliferi Mountains. EEFEEENCES Berbeleac I. (1975) Studiul petrografic și metalogenetic al regiunii Vălișoara (Porcurca) (Munții Metaliferi). An. Inst. geol. geofiz., XLVI, 1 — 190, București. Berbeleac I., Da vid Margareta (1980) Native Tellurium from Musariu, Brad Region (Metaliferi Mountains), Romania. Miner. Deposita, (in press). Borcoș M., Berbeleac I., Gheor g h i ț ă Ioana, B r a t o s i n I r i n a, C o 1 i os Elena, Z ă m i r c ă A 11 a, Ana sta se S., Verdeș Gh., Stănescu I. (1980) Chemical Remarks on the Valea Morii Porphyry Copper Ore Deposit (Metaliferi Mountains). D.S. Inst. geol. geofiz., LXIV, 17 — 36, București. Borcoș M., Manii ici V. (1965) Geothermometric Analysis — a Criterion for the Determination of Thermodynamic Conditions of Hydrothermal Mineralization. Sympo- sium „Problems of Postmagmatic Ore Deposition”, II, 356—363, Praga. Dana J. D., Dana S. E. (1961) System of Mineralogy. 7th ed. entirely rewriten and en- larged by Palache Eh., Berman H., Frondei C., I, 834, New York-London. F o 1 i n s b e e E. R. (1919) Determination of Reflectivity of the Ore Minerals. Econ. Geol-, 44, 5, 425-436. G h i ț u 1 e s c u T. P., Soc ol eseu M. (1941) Etudc geologique et miniere des Monts Metaliferes (quadrilatere aurifere et regions environnantes). An. Inst. Geol. Roum., 1—126, București. Giușcă D. (1936) Nouvelles observations sur la mineralisation des filons aurifăres de Săcă- rimb. Bull. Acad. Roum. Sci., 18, 3 — 5, 97 — 103, București. — (1937) Le chimisme de la nagyagite. Soc. Roum. GM., III, 118 — 121, București. Helke A. (1934) Die Goldtellurerzlagerstătten von Săcărîmb in Rumănien. A'. Jahrb. V. Min., 68, 19 — 85. — (1938) Die Jungvulkanischen Gold-Silver-Erzlagerstătten des Karpatenbogens unter besonderer Berucksichtigung der Genesis und Paragenesis des gediegenen Goldes. Arch. Lagerstătten forschung, 66, Berlin. Ia novici V., Giușcă D., G h i ț u 1 e s c u T. P., Borcoș M., Lupu M., B 1 e a h u M„ Savu H. (1969) Evoluța geologică a Munților Metaliferi, Ed.. Acad., 741 p., București. Ia no viei V., Borcoș M., Bleahu M„ Patrulius D., LupuM., Dimi- t rescu R., Savu H. (1976) Geologia Munților Apuseni, Ed. Acad., 631 p., București- I a n o v i c i V., V 1 a d Ș., Borcoș M., Boștinescu S. (1977) Alpine Porphyry Copper Mineralization of West Romania. Miner. Deposita., 12, 307 — 317. Ma rkham N. L. (1960) Synthetic and Natural Phases in the System Au-Ag-Te. Econ. Geol., 55, 6, 1148-1178. Institutul Geological României 168 I. BERBELEAC 16 M ii h 1 e r I. V. (1884) Vortsetzung der Versuche mit dem in der Grabe Half in dem Facenz- baya bei Zlatna vorkommenden Spiessglaskonig. Physik, Arb. eintracht. Freunde, I, 2, 49-53. R a m d o h r P., Udubașa G. (1973) Frohbergit — Vorkommen in den Golderzlager- stătten von Săcărîmb und Fața Băii (Rumănien). Miner. Deposila, 8, 179 — 182. Ramdohr P. (1975) Die erzmineralien und ihre Verwachsungen, 1277 p. Berlin. Ră du 1 eseu D., Dimitrescu R. (1966) Mineralogia topografică a României. Ed. Acad., 376 p.. București. Schrauf A. (1878) Ober die Tcllurerze Siebenburgens. Z. Kristallogr. Bd. 2, 3, 209 — 2 52. Thompson R. M., Peacock A. M., Rowland F. J„ B r a d 1 e y G. L. (1951) Empressite and „Stuetzite”. Amer. Mineralogiei, 36, 5—6, 458—490. Uytenbogaardt W„ Burke J.A.J. (1971) Tables for Microscopic Identification of Ore Minerals. Second revised edition, 433 p., Amsterdam, London, New York. V I a s o v A. K., Ed. (1966) Geochemistry and Mineralogy of Rare Elements and Genetic Types of Their Deposits. II, 945, English translation, Jerusalim. EXPLANATION OF PLATES Plate I Fig. 1 — Gleavage and trîangular and irregular pits in native tellurium. Veinlet no 2 ; Nic//, X 125. Fig. 2 — Quartz and pyrite inclusions in compact aggregates of native tellurium. Veinlet no 2 ; Nic II, X 125. Fig. 3 — Drop inclusions of native tellurium (white) and polygonal grains of nagyagite (grey) in twinning sylvanite. Veinlet no 1 ; Nic //, x 240, in oii. Fig. 4 — Euhedral crystal of nagyagite within sylvanite (white and grey with lamellar twin- ning) and native tellurium (dark grey in the left corner of the picture). Veinlet no 1 ; Nic //, X 250, iu oii. Plate II Fig. 1 — Intergrowth of native tellurium (grey-white) and krennerite (dark grey). Note the distinct optical contrast between the two above mentioned minerals and pyrite in- clusions. Veinlet no 1 ; Nic +, x 250, in oii. Fig. 2 — Unidentified telluride with mirtnekilic texture (grey-white) and native tellurium (right corner down). Remark the well polished pyrite (white) and quartz inclusions. Veinlet no 1 ; Nic +, X 250, in oii. Fig. 3 — Intergrowth of hessite (grey), tellurium (white-grey with triangular pits) and uni- dentified telluride with mirmekitic texture. Veinlet no 1 ; Nic II, X 250, in oii. Fig. 4 — Filling fissure with empressite in tellurium. Veinlet no 1 ; Nic +, x 250, in oii. Institutul Geological României CONTRIBUTIONS TO THE KNOWLEDGE OF THE HYDROGEO- THERMAL STRUCTURES IN ROMÂNIA AND OF THE PROSPECTIVE ZONES1 BY CONSTANTIN GHENEA, TODERIȚĂ BANDRABUR, PETRE CRĂCIUN, ANA GHENEA2 Thermal waters. Hydrogeothermal structures, Geothermy. Geothermal gradient. Applied hydrogeology (character istics). Hydrogeologic drillings. Hijdrogeothermal resources. Ro- mânia. Pannonlan Depression. Moesian Platform. East Carpathians. South Carpathians. Apuseni Mountains. Transyloanian Depression. Sommaire C o n t r i b u t i o n s ă Ia connaissance des structures h y d ’ o- găothermales de Roumanie et des zones de perspective. L’on- vrage represente une synthese des donnees concernant les structures d’eaux thermales de Roumanie. On y prăsente aussi des donnees obtenues par l’dtude d’un vaste maUriel (les tempăratures mesurees en nombreux sondages d’hydrocarbures) concernant le regime geo- thermique de quelques unităs structurales. La correlation de ces donnes avec les particulari- tes hydrogăologiques a mend â des conclusions sur l’eventuelles zones de perspective pour les eaux thermales. I. Introduction The paper represents a synthesis of the data referring to the thermal waters in Romania; with that end in view a rich documentary material has been studied. For the assigning of the information obtained in the ensamble represented by the geothermal energy and its utilization as energy mass, the temperature data of some formations measured in wells 1 Paper received on February 5, 1980 and accepted for publication on March 25, 1980. 2 Institutul de geologic și geofizică, str. Caransebeș nr. 1, 78344, București. Institutul Geological României 170 C. GHENEA et al. 2 have also been processed. The correlation of the geological-structural conditions, of the hydrogeological features of certain units as well as of the geothermal anomalies identified led to the establishing of the possi- bilities of making evident of some prospective zones for thermal waters. Among the numerous studies elaborated in the last century refer- ring to various aspects of the thermal water deposits, only those with a general character worked out recently will be mentioned here. Thus, beginning with L i t e a n u et al. (1965) the series of synthesis papers continued with the papers of Vas ilescu and N e c h i t i (1968), P r i c ă j a n (1972), P a r a s c h i v et al. (1975), Vasilescu and Opran (1975), A 1 i-M e hmed et al. (1976), etc. There is also a large number of regional reports on the prospection works and explora- tions for thermal waters carried out by the Ministry of Mines, Petroleum and Geology on the whole Romanian territory in the last decade (I c h i m etal.,19713; Nechiti et al., 19714; Bandrabur etal., 1975—19795). II. The Hydrogeothermal Structures in the Great Structural Units. Geothermal Features. Hydrogeological Considerations As the degree of knowledge of the thermal water potențial is, up to now, different, we shall present the results obtained in each major struc- tural unit according to the importance of this potențial. To this purpose, this papei deals with the problema specific to the Pannonian Depression Fig. 1. — Structural units of Romania. a București I, East Carpathians; II, South Carpathians ; III, Apuseni Moun- tains ; IV, neovolcanic mountains ; V, Moldavian Platform ; VI, Moe- sian Platform; VII, North Do- brogea and Predobrogean Depres- sion; VIII, Pannonian Depres- sion ; IX, Transylvanian Depres- sion ; X, Getic Depression; XI, Neogene zone danuqe BULGARIA (the easternmost part including the Romanian territory, the Moesian Platform, the Getic Depression, the East Carpathians, the South Car- pathians, the Apuseni Mountains, the Transylvanian Depression (Fig. 1). 3, 4 Arch. M.M.P.G., Bucharest. 5 Arch. I.G.G., Bucharest. L- Institutul Geologic al României 3 HYDROGEOTHERMAL STRUCTURES IN ROMANIA 171 1. The Pannonian Depression (the Romanian Territory) Structural Elements. The main infoi'mation on the deep limits of the earth’s crust has been emphasized by the seismic data of the last seg- ment on the Romanian territory on the llth International Profite (R ă- dulescu et al., 1976). The characteristic feature of the Mohorovici discontinuity of this profile consists in its regional uplift (27 km). Howe- ver, the decrease of the thickness of the earth’s crust has been registered on the Hungarian territory, as well (24—26 km). Against this general background, the structural map (Fig. 2) points out the existence of major fractures whose movements on the vertical affected both the crystalline basement and the covering sedimentary formations. These fractures with two predominant direetions — NW-SE and NE-SW — separate se- veral sink and uplift compartments. The Pre-Neogene relief of the depres- sion with such a configuration determines various thicknesses of the co- vering formations, from some metres in the uplift compartments in the vicinity of the Apuseni Mountains to more than 4,000 m in the sink com- partments. As the main hydrogeothermal structures are situated at the level of the Upper Pannonian (s.l.) it is to be mentioned that, within this struc- tural edifice, several zones characterized by an active subsidence in the whole Pannonian have been distinguished: Satu Mare, Galoșpetreu- Mecențiu, Socodor-Grăniceri, etc. (Fig. 3). Geothermal Regime. Starting from the thermal sources known due to the natural emergences in the Oradea zone, several research hydro- geological drillings have been carried out in recent times. Then, the sys- tematic investigations conținu ed with measurements of the temperature in the bore-holes, at different stratigraphic levels, most of them effectua- ted in the research bore-holes foi’ hydrocarbons. At present, the available data allowed the drawing up of a geoiso- thermal map at a reference plan of — 1,000 m. In most of the depression, it corresponds to the average depth of the aquiferous complex of the Upper Pannonian, the main reservoir known both in Romania and in Hungary (Fig. 4). Although there is a certain degree of approximation of the results due to the ununiform distribution of the bore-holes where the measurements have been accomplished, several positive anomalies with high values are individualized in the above-mentioned map. Thus, in the Someș- Crișul Repede interfluve an anomaly with values exceeding 80°C is out- lined in the Săuca-Mecențiu-Moftinu zone. This anomaly extends west- ward (Cărei) where it reaches 90 —95°C. Structurally, it is situated on a sink compartment, with a sedimentary cover of about 3,100 m. West- ward, there is an anomaly, with smaller values (78—85°C), in the Pișcolț- Curtuiușeni ar ea. Another anomaly, with a relative small extension, corresponds to the Abrămuț sector (80°). To the west, in the Săcuieni zone, one can notice relatively high values (75—85°), structurally corresponding to a compart- ment where the crystalline basement is at a depth of about 2,000 m. In Institutul Geological României 172 C. GHENEA et al. 4 Fig. 2. — Structura1 map of the Pre-Neogene relief (Pannonian Depressiou). 1. isobath of the Pre-Neogene relief; 2, Pre-Pannonian fault; 3, Post-Pannonian fault; 4, fault resumed in the Pannonian; 5, eastern border of the Pannonian Depressiou. E Institutul Geological României 174 C. GHENEA et al. 6 Fig. 4. — Distribution of the Upper Pannonian temperatures. 1, isogeotherm of 70° at — 1000 m elevation; 2, eastern border of the Pannonian Depression. Institutul Geological României 7 HYDROGEOTHERMAL STRUCTURES IN ROMANIA 175 the more Southern zones, Chișlaz-Cenaloș-Sălard-Tămășeu, the isotherms indicate a decrease of temperature below 70°C, except the Ciulești ano- maly with an isotherm of 80°C. In the Borș-Oradea zone there are no anomalies with high values at the Pannonian level. The temperatures range between 50°—70°C with a tendency of decrease westward. In the region between the Crișul Repede and the Mureș rivers, the small bulk of data did not permitted a minute study of the thermal field. Values exceeding 65°C are locally recorded to the west of the Miersig- Tăutu-Chișinău Criș alignment. In the, Southern part of the study region there is the Turnu struc- tural zone with isotherms of 75 and 80°C. In this area, the anomaly has been controlled by the geothermal gradient in steady state regime and recorded in bore-holes at depths of 20 m and 30 m, respectively (V e 1 i c i u, 1974) 6. South of the Mureș River, in the Calacea-Șandra and Variaș zones, there are two anomalous areas characterized by anomalies of 65—85°C for the former and 65—70°C for the latter. These areas correspond to uplifts of the crystalline basement at depths of 1,000—1,500 m. Hydrogeological Features. In the study region aquiferous complexes appear in Triassic, Cretaceous and Pannonian formations. The Triassic aquiferous complex occurs only in the Oradea zone, where the thickness of the Triassic formations reaches 1,000 m. In limes- tones and dolomites, the drillings came across waters with artesian dis- charge capacity up to 800 c.m/day and temperatures of 87° and 90°C. The Cretaceous aquiferous complex is known by the thermal waters of the Băile Felix and 1 Mai resorts. At Băile Felix, the artesian discharge capacity amounts to 17,000 c.m/day and temperatures of 49.5C. The inferior levels are characterized by lower temperatures and smaller dis- charge capacities. The Upper Pannonian thermal aquiferous complex represents the main thermal water reservoir in the Pannonian Depression. Its thickness exceeds 1,000 m in the interior of the sink compartments. In order to point out the regional distribution of temperature hori- zontally and on the vertical within this thermal aquiferous complex, a hydrogeothermal map has been drawn up, which represents a correla- tion of the map with isotherms at — 1,000 m and the development of the permeable Upper Pannonian horizons (Fig. 5). The examination of this map pointed to zones with favourable geothermal characteristics, the structural features being also emphasized. It is to be mentioned the sectors situated along the Cadea-Galoșpetreu- Andrid-Mecențiu sink zone, where the temperatures measured at the base of the thermal complex would indicate 140°C. In a more northern zone — — Satu Mare-Moftinu — the temperature exceeds 80°C at the level of the thermal aquiferous complex. 6 Arch. I.G.G., Bucharest. Institutul Geologic al României 176 C. GHENEA et al. 8 Fig. 5. — Hypothetical temperatures of the thermal aquiferous complex (Upper Pannonian).. 1, temperatures < 50°; 2, temperatures = 50—60°; 3, temperatures = 30—80°; 4, tempera- tures = 80—100°; 5, temperatures> 100°. Ă Institutul Geologic al României XJGR/ 9 HYDROGEOTHERMAL STRUCTURES IN ROMANȚA 177 South of the Crișul Repede River, there is the Socodor zone with temperatures of about 100°C and the Salonta zone with temperatures exceeding 60°C. The hydrothermal drillings already carried out indicated that most of the Upper Pannonian aquiferous complex has artesian discharge (the piezometric level ranges between +2 and 87 m). The yield varies within Avide limits, from some tens of cubic metres/day to 2,000—3,000 c.m/day, depending on the permeability and thickness of the aquiferous complex. In the whole area of the thermal aquiferous complex, one can notice a decrease of the water temperature towards the easternrnost part of the depression due to the cold water supply from the border as well as the higher position of the sand horizons in this part of the unit. 2. The Getic Depression Structural Elements. From the geological and structural point of view, the Getic Depression corresponds to the depression area in front of the South Carpathians, defined as a unit at the end of the Cretaceous and as sedimentary basin during the whole Tertiary. From the succession of the cycles of sedimentation occurring in the evolution of this unit, interesting for the formation of hydrogeothermal structures are the deposits in coarse facies belonging to the Senonian and Lower Eocene, the Burdigalian eonglomerates, certain Badenian horizons with coarse facies especially towards the border zones of the Getic De- pression, partly certain Sarmatian and Pliocene levels, where sediments with a lithology favourable to the accumulation of the thermal aquiferous complexes developed. The sedimentary complex of the Getic Depression has been affec- ted by rumpled and disjunctive movements. They result in several folded structures, aligned parallel to the South Carpathians. Each structural alignment consists of several interrupted anticlines and synclines or faul- ted fragments. The structural complications become more obvious with the increase of the depth and the age of the formations. On the whole, the sedimentary formations sink from the north to the south, in the sense in which this unit formed and developed. As a result, the rumpled elements are constituted of more and more recent formations as we go to the exterior flank of the foredeep, and the folds trend generally south wards (M o t a ș et al., 1966) 7. The degree of tectonic complexity of the structural elements which influence the thermal flow also results from the study of a profile in the eastern part of the depression on which the isogeotherms of 75—120°C have been plotted (Fig. 6). Geothermal Regime. The estimation of the zones for thermal waters has been made almost exclusively on the basis of the temperature measu - rements carried out in the hydrocarbon wells. The distribution of the ob- ’ Arch. M.M.P.G., Bucharest. 12 - c. 658 L- Institutul Geologic al României 178 C. GHENEA et al. 10 Fig. 6 — Geological cross-section through the Getic Depression. 1, Upper Neogene; 2, Lower Neogene; 3, Paleogene; 4, Cretaceous; 5,Jurassic; 6, crystal- line : 7, overthrust; 8, fault; 9, isogeotherm. Fig. 7. — Geothermal gradients in the Getic Depression. servation points was not uniform; however, the interpolation of the data in the areas with insufficient observations has been avoided at the drawing up of the map with the geothermal isogradients (°C/100 m) (Fig. 7). The map emphasizes certain zones with slightly high values of the geothermal gradients generally varying from 3 to 4°C/100 m. For the estimation of the possibilities concerning the existence of aquiferous complexes in the zone of the positive geothermal anomalies, the temperature data have been correlated with the geological structure of certain sectors where there are conditions favourable to the aquiferous accumulations. An example pointing to the method used for the estima- tion of this prospect is shown on Figure 6. Hydrogeological Features. The existence of thermal waters in the Getic Depression was recognized owing to springs occurring in the Căli- mănești-Căciulata zone. Relying on these indications with a view to obtai- ning increased yields necessary to the development of the resort, drilling Institutul Geological României 11 HTOROGEOTHERMAL STRUCTURES IN ROMANIA 179 works with important results have been carried out recently. Thus, in the Căciulata-Călimănești zone thermal waters have been rendered evident at depths varying from 198 to 1,250 m, accumulated in the Seno- nian and Lower Eocene fissured conglomeratic packets. The waters are characterized by temperatures ranging between 25—53°C and minerali- zations of 2.5—20 g/1 (chloro-sodic and bromo-iodurate sulphurous wa- ters) (G o 1 i ț ă, 1974) 8. At Bala, the thermal waters occur in the Badenian psephitic deposits at depths varying from 30 to 160 m. Thermal waters have also been pointed out in the drillings carried out in the Țicleni structure, at a depth of 2,020—2,800 m (Lower Mio- cene). The temperatures range between 85—92°C, with discharge capaci- ties of 172—500 c.m/day. As mentioned before, the analysis of the geothermal anomalies ac- cording to the hydrogeologic conditions specific to each structure of the Getic Depression leads to the conclusion that there are premises favourable to the existence of other hydrogeothermal structure, as well. From this point of view, they are interesting for possible prospecting works in the sectors located near by the main dislocations, where the Cretaceous, Paleo- gene and Miocene formations partly developed in psamopsephitic facies. 3. The Moesian Platform Structural Elements. The Moesian Platform is delimited by the Peri- carpathian Depression to the north, the Prebalkans to the South, and the North Dobrogean Orogen to the northeast. This unit is characterized by a basement made up of greenschists in the eastern part and crystalline schists in the western part, overlain by a sedimentary cover within which several cycles have been separated: Oambtian(?)-Carboniferous, Per- mian-Triassic, Jurassic-Cretaceous, Neozoic. The works carried out recently by means of the prospecting geo- physical methods and mostly controlled by the hydrocarbon research drills outline the structural elements of the Platform. Against the back- ground of gradual sinking to the north of the Pre-Neozoic formations, one can notice regional archings indicating the existence of structural elements in the Mesozoic or older formations. A significant uplift lies in the easternmost part of the Platform and corresponds to the northeastern prolongation of Central Dobrogea. The other two are located in the wes- tern part and correspond to more ample anticline bulges. The above-mentioned uplifts are separated by several depressions which render evident some morphostructural differences more obvious at the level of the first cycle of sedimentation. The tectonic aspect of the Platform is complicated by a network of vertical fractures which affect especially the basement and the Paleo- zoic and the Mesozoic formations. In most cases the fractures delimit the 8 Arch. I.G.P.S.M.S., Bucharest. Institutul Geological României n 1GR 180 C. GHENEA et al. 12 compartments of Systems of horsts and grabens wherein the thickness of the same sedimentary complex can be different. Geothermal Regime. The geothermal regime characteristic of the Moesian Platform has been cleared up due to the temperature measure- ments accomplished mostly on the occasion of the hydrocarbon drilling works. Their distribution points out the existence of a rich bulk of data in the central and northern part of the Platform, in the southernmost part (the Danube River zone) the measurements being sporadic. The depths measured in the northern half (exceeding 2,000 m) also correspond to the areas where the proposed objectives referred to the Triassic, Jurassic and Cretaceous formations .In more Southern and eastern zones, the researched levels are located at smaller depths (below 1,000 m) and correspond to the Sarmatian deposits. Provided the ununiformity of the depths where the measurements were accomplished and the different geothermo-dynamic conditions during the recording of the temperature in the bore-holes, it has been drawn up a sketch-map representing the temperature distribution at a depth of 1,500 m, a level with a median position as compared to the depths where the geothermal data come from (Fig. 8). The position of the main geother- Fig. 8. — Geothermal gradients in the Moesian Platform. mal anomalies indicate that they partly overlie the major tectonic lines generally trending W-E. This map renders evident several anomalies de- veloped even along the tectonic alignment constituted by the Pericar- pathian fault. In the region west of the town of Bucharest, a significant geother- mal anomaly corresponds to the Ciurești-Videle major fracture. Institutul Geologic al României 13 HYDROGEOTHERMAL STRUCTURES IN ROMANIA 181 East of Bucharest, although the available data do not indicate areas with extended geothermal anomalies, the sectors with high tempera- ture outlined at însurăței and Bordeiu Verde occur in continuity of the Ovidiu-Capidava major fracture. The position of these geothermal anomalies shows that the transmis- sion of the heat flow to the surface takes place along these deep fractures. Up to now we have no geothermal data on the Precambrian base- ment in the Moesian Platform. Ilydrogeological Features. Thermomineral water occurrences in the Moesian Platform are known in some points. At Mitrofani, in the Dogger limestones and sandstones thermal waters with temperatures of 91°C and yields of 12 c.m/hour occur at a depth of about 4300 m. At Piua Petrii the drillings came across waters with temperatures of 58°C in the Cretaceous limestones at depths of 280 and 302 m. South of the Danube, thermomineral waters occur at Topalu and Hirșova from the Jurassic limestones outeropping in this area. Incertain bore-holes the water temperatures reach 52°C. In the south-eastermnost part, in the Mangalia resort region, the drillings percolated Jurassic limestones with water accumulations with temperatures of 26°C. In the Sarmatian limestones at the upper part, a second mesothermal complex seems to develop (20—26°C) with sulphur- chloride-sodium waters with a H,S content of 1.5—9.7 mg/1 (Fig. 9). 23August Mangalia I sm |! I Pg I? I sn |3 | cm h | br |ș \j^j3 |ș | t> |? | y 18 | S Fig. 9. — Schematic cross-section in the Mangalia area. 1, Sarmatian ; 2, Oligocene ; 3, Senonian ; 4, Cenomanian ; 5, Barremian ; 6, Middle and Upper Jurassic; 7, Devonian; 8, Silurian; 9, thermal water paths. Institutul Geological României 182 C. GHENEA et al. 14 Taking into account the lithologica! constitution of the Paleozoic, Mesozoic and Neozoic formations in the whole Moesian Platform, the exis- tence of thermal aquiferous complexes in the sectors with geothermal anomalies is very likely. 4. The East Carpathians Geothermal Regime. The geothermal features of the East Carpathians are generally less known due to the small number of thermal sources of the measurements accomplished directiv in wells. Among the structural units, in the Călimani-Gurghiu-Harghita neo-volcanic zone there are in- dications of a geothermal field with high values. The geothermal anomalies generally occur either along the western border or the eastern one, at the contact of the volcanic chain with the Transylvanian Depression. Geological and geophysical researches in the zone of the neo-erup- tive chain pointed out a System of deep-seated dislocations connected with the emplacement of the eruptive masses. The geothermal regime is influenced by this magmatic chamber which gave rise to the youngest volcanism in the Carpathians. For the estimation of the geothermal conditions in the zone of the Călimani-Gurghiu-Harghita volcanic chain, there were taken into account the thermal water occurrences, the data obtained from the hydrogeother- mal drillings with a view to knowing the geological and hydrogeological conditions of the zone and the geothermic prospections at small depths carried out in certain sectors. Schematically, the Information at our disposal is rendered in Figure 10. From the north to the south, there are indicated the temperatures measured in wells and thermal waters in the Lunca Bradului and Toplița zones, the gradients of about 8—10°/ /100 m in the. Vlăhița wells ascertained by geothermometric geophysical prospections (Vel ic iu, 1975) 9, in the wel-known thermal waters at Tușnad Băi where recently both the core drills and the geothermometric measurements of small depths pointed out anomalies of 10— 15°C/100 m. The development of the Neogene volcanism, which have taken place during several stages in the East Carpathians is also proved by the magmatic products in the northern part of the Carpathians, in the Oaș- Gutîi Mountains zone. In this area there are some indications on the ther- mal regime as a result of the measurements-carried out in dry rocks in mines or of the rare thermal water occurrences (Fig. 11). In other structural units of the East Carpathians there are very few data on the thermal regime. Inthe Crystalline-Mesozoic zone in the sou- thernmost part (Brașov and Codlea) there are indications referring to the existence of a relatively high geothermal field at the level of the Creta- ceous conglomerates and the Triassic carbonatites. 0 Arch. I.G.G., Bucharest. Institutul Geologic al României 15 HYDROGEOTHERMAL STRUCTURES IN ROMANIA 183 Fig. 10. — Distribution of hydrogeothermal resources in the East Carpathians. 1, depressions ; 2, neovolcanic mountains ; 3, Neogene zone ; 4, Cretaceous-Paleogene flysch • 5, Crystalline-Mesozoic zone; 6, thermal water sources; 7, rock temperature at 2000 m deep ; 8, geothermal isogradient. 184 C. GHENEA et al. 16 Fig. 11. — Sketch with geothermal locations in the Oaș-Gutii Mountains. Quaternary; 2, Pannonian; 3, Lower Pannonian; 1, Paleogene; 5. andesites; 6, thermal water sources. » Arch. LG.P.S.M.S. Bucharest. Institutul Geological României 186 C. GHENEA et al. 18 on pointed out waters with temperatures of 63°C and artesian discharge capacities of about 4.2 1/sec. The results obtained at Tușnad seem to prove the conclusion that the neo-volcanic zone of the East Carpathians represents a zone with real prospect» of the use of the geothermal anomalies as sources of uncon- ventional energy. 5. The South Carpathians The South Carpathians are mostly constituted of crystalline schists with a nappe structure and preserved, in some basins, a less extended Paleozoic-Mesozoic cover connected with hydrogeothermal structures. Hydrogeological Features. The manifestations of the hydrogeother- mal activity are restricted to the Southern segment; the best-known zone is situated in the Cerna Basin, in the Herculane spa zone. The recent geo- logical and structural researches (N ăsta sea nu, 1974)11 allow a good characterization on the Herculane structure. The tectonic style of the region is characterized by tight folds trending NNE-SSW. strongly affected by cross faults which determine the shifting of some compart- ments to W-E. In the Herculane zone, the most significant structural elements are represented by the Getic nappe, the Cerna graben, the Cerna anticline and syncline, all of them trending N-S. The Cerna graben is delimited by two longitudinal faults. To the west of the western fault there is the Cerna anticline and syncline. In the axis of the Cerna anticline there is the Cerna granițe; the eastern flank is faulted and fallen to the graben (Fig. 13). The Cerna anticline and syn- cline sink to the north-south along faults with most of the thermal water sources in this zone. In the Jurassic limestones and in the Cerna granițe, a deep-seated aquiferous complex, characterized by high temperatures, has been empha- sized. The water temperature at Herculane varies from 17 to 6.5°C; the radioactivity points to maximum values of 21.46 m Ci/l, but it decreases to the south, reaching 3 m Ci/l. The chloro-sodic-calcic mineralization reaches 8.2 g/1 in certain sources. The origin of the thermomineral waters at Herculane has been dis- cussed for a long time and explained either as infiltration waters or as juvenile waters (bromine and iodine ions frequently occur). The geother- mal regime of the Herculane zone is characterized by the individuali- zation of an anomaly with a geothermal gradient of 4.5°C/100 m. It has been considered that the fractu re zones which extend in the granitic massif form preferențial access ways of the heat flow from the upper part of the cover. It is about a differential spreading with high gradients in the areas of the cross fractures where the underground water also has a more in- tense ascensional circulation. 11 Arch. I.G.G., Bucharest. 19 HYDROGEOTHEBMAL STRUCTURES IN ROMANIA 187 Outside the Herculane zone, in the South Carpathians there are thermal water occurrences at Mehadia, in a Neogene basin with partly permeable formations. The drillings pointed out an aquiferous complex under pressure, with water temperatures of 31°C (S i m i o n, Popa, 1971)12. Thermal waters also occur at Ciclova Montană (29.5°C), at Carașova (19.5°C), the Miniș Valley (19.5°C) and at Călan (25—29°C). Fig 13. — Geologica! cross-sect:on at the Herculane Spa (after S. Năstăseanu). 1, Senonian : 2, Barreinain-Aptian ; a, limestones ; b, inarls and limestones; 3, Valanginian-Hauterivian (marls and limestones); 4, Upper Jurassic (limestones); 5, Middle and Lower Jurassic (sandstones); 6, crystalline (Getic nappe); 7, crystalline and gra- nitic rocks : 8. fault. 6. The Apuseni Mountains The Apuseni Mountains have a complex geological-structural cons- titution, being formed of several nappe units and an autochthon with a mostly Mesozoic cover. On the western side of the Apuseni Mountains there occur several gulfs which have generated Neogene basins where there are numerous thermal water occurrences. Sydrogeological Features. Up to now we have very few available data on the geothermal sources and they coincide with structures revea- led by the exploitations. The best-known zone with thermal water occurrences is at Moneasa, in the Southern zone of the Apuseni Mountains, in a nappe zone mostly consisting of Carboniferous, Permian, Triassic and Jurassic formations. The thermal waters springfrom the Triassic calcareous formations nearby the contact with the Permian impermeable rocks (the basic volcanogenous i- Arch. I.G.P.S.M.S., Bucharest. Institutul Geologic al României 188 C. GHENEA et al. 20 series, tufaceous sandstones, etc.) (Fig. 14) (O r ă ș e a n u, N ieo 1 e O r ă ș e a n u, 1974) 13. The temperatures of the thermal waters in the Moneașa zone range between 15—32.5°C, with higher values near by the overthrust plaiie. Fig. 11. — Geological sketch with the distribution of the hydro- geothennal resources of Moneasa. 1, Holocene; 2, Lower Jurassic: 3, Triassie; 1, Permian; 5, ther- mal spring; 6, thermal water bore-hole. The total yield of the four main springs amounts to 19.9 J/sec. and of those uncatchmented in the central zone of the resort amounts to 43 1/sec. Another hydrogeothermal structure is that in the Geoagiu zone, in the south-easternmost part of the Apuseni Mountains, in the Mureș Valley region. 13 Arch. I.G.P.S.M.S., Bucharest. Institutul Geologic al României 21 HYDROGEOTHERMAL STRUCTURES IN ROMANIA 189 The drillings carried out. in the Geoagiu zone stopped in crystalline limestones overlain by Upper Cretaceous marls and sandstones, with thicknesses of tens of metres range. The sequence ends with Quaternary travertines of about 10—15 m thick. At Geoagiu Băi it has been pointed out a System of faults affecting both the crystalline limestones and the Fig. 15. — Sketch with the distribution of tlie hydrogeothermal resources in the Apuseni Mountains. 1, Neogene sediments; 2, Pre-Neogene sediments ; 3, Neogene vol- canic rocks; 4, Pre-Neogene magmatic rocks; 5, crystalline rocks; 6, thermal water sources. Cretaceous deposits. On these faults, the waters occurring at surface have temperatures of 20°C whereas in bore-holes the temperature reaches. 32°C (150 m deep). Institutul Geological României 190 C. GHENEA et al. 22 In the Geoagiu zone, the geophysical prospections (geothermy) also emphasized several local anomalies which attest the existence of zones with high geothermal gradients. The hydrogeothermal deposit at Vața de Jos is located in the Crișul Alb Valley, in a region characterized by a complex of basaltic rocks with a high degree of fissuring and alteration. The drillings carried out at a depth of 110 m stopped in the basaltic complex. The thermal waters which spring from depth along major fractures have temperatures varying from 38 to 39°C and (discharge capacities of 4 1/sec. In a restricted area, around the Vața resort, geothermal prospections by core drillings outlined two anomalies characterized by waters with temperaturse of 25—30°C (V e 1 i c i u, 1976). In the Neogene basins on the western border of the Apuseni Moun- tains thermal waters occur at Băbăgani-Luncasprie-Corbești. At the con- tact of the Neogene detrital sediments with the Mesozoic calcareous formations (karstified Triassic and Cretaceous limestones) there occur waters with temperatures ranging between 19—37°C and yields of 15 1/sec. In the Zarand basin, in the Beliu-Cărand-Buteni sector, thermal waters occur both from springs and from drillings. The most interesting results have been obtained in the Cărând bore-holes where at 450—1,000 m deep there are waters with temperatures reaching 44°C and discharge capacities of 3—80 1/sec. In the Silvania basin, where the crystalline basement is overlain by Badenian and Pannonian formations, several drillings have been car- ried out with a view to prospecting hydrogeothermal structures. In the localities of Zalău, Boghiș, Șimleul Silvaniei the water temperature varies from 24 to 43°C and discharge capacities which sometimes reach 25 1/sec. A sketch-map of the main thermal zones in this unit (Fig. 15) has been drawn up for the estimation of the prospects of the geothermal re- sources in the Apuseni Mountains. 7. The Transylvanian Depression The Transylvanian Depression lies in the interior of the Carpathian Arc. It has a tectonic origin and a basement consisting of crystalline schists and sedimentary formations including the Lower Cretaceous and the filling sedimentary formations comprising the Upper Cretaceous, Paleogene, Miocene and Pliocene. Geothermal Regime. For the estimation of the thermal field one used some of_țhe temperature data recorded in the drillings carried out with a view to outlining the natural gas deposits. The values obtained for rela- tive small depths corresponding to the proposed geological objectives (about 1,000 m) are, in general, higher than those recorded at greater depths (2,000 m). Considering also the small bulk of data, the value of the geothermal gradient calculated is rather informative; however, it Institutul Geologic al României 23 HYDROGEOTHERMAI. STRUCTURES IN ROMANIA 191 points to the conditions of transmission of the heat flow at the level of the sedimentary cover in the Transylvanian Depression. The regional sketch-map (Fig. 16) outlines the central part of the Depression, several data corresponding to the gas structures. The values of the geothermal gradients vary from 2 to 3°C/100 m. At the north- Fig. 16. — Distribution of temperatures in lhe Transylvanian Depression. 1, geothermal data bore-holes; 2, thermal water bore-holes; 3, geo- thermal isogradient. eastern part of the Depression (Corunca-Ernei) one can notice higher values of the gradient: 3—3.95°C/100 m. In conclusion, it 'has been considered that in the Transylvanian Depression there is a geothermal anomaly of a poor intensity situated at the base of the sedimentary cover. The molasse structure of the unit, slightly affected by phenomena of disjunctive tectonics is not favourable to natural conditions of intensive transmission of the heat flow in the upper part of the sedimentary massif, a phenomenon evidenced in the units with more frequent deep-seated fractures. 192 C. GHENEA et al. 24 Hydrogeological Features. The best known hydrothermal structure lies on the eastern border of the Depression, in the typical development zone of the salt diapir massif. The drilling works which. were aimed at the research of the salt massif of Praid came across, at the salt breccia level, thermal waters with an inițial temperature of 60°C. During several years, the temperatures decreased to 42—45°C, a quite significant reduction of the discharge capa- city of the aquiferous complex being also noticed. Due to the very high degree of mineralization (122—231 g/1) as a result of the washing of the salt massif, the thermal waters are used for the balneary cure. The mineralized (chloro-sodic) thermal waters occur at Brătei, at a depth of about 3,000 m. The water yields are of about 3 1/sec, and sur- face temperatures of 60°C. At Ruși, the water temperature is 38°C and the discharge capacity is 10 1/sec. Finally, temperature measurements on rocks, carried out at Mociu, allowed the drawing up of the thermogram : 45.5°C at 500 m ; 75°C at 2,000 m ; 85°C at 3,500 m and 93.5°C at 4,000 m. III. Conelusions on the Present Stage and the Reeovery Prospeets of the Termal Waters In Romania, the thermal waters are used for balneary purposes in some spas of a național and internațional importance : Băile Herculane, Felix, Căciulata, Geoagiu, Moneasa, Mangalia. Recently, more than twenty localities become local balneary or recreation centres : Vata, Tușnad, 1 Mai, Toplița, Vlăhița, Oradea, Timișoara, Arad, etc. In the western part of Romania, the hydrogeothermal resources, having high temperatures and discharge capacities, are used in district heating of the town of Oradea. In recent times, a special concern is in connection with theutilization of the thermal waters at the flower and vege- table greenhouses. The utilization of thermal waters in industry (textile industry) is already an achievement. In technics the researches for the obtaining of electric energy from the thermal waters with a low enthalpy are being carried out (80—100°C). The systematic studies, used in the future for the geothermal charac- terization of certain geological units, are aimed at the reeovery of the dry rock heat as a new source of energy necessary to the future development of industry. REFERENCES A i r i n e i Șt., P r i c ă j a n A., B a n <1 r a b u r T. (1976) Conceptual Pattern Concerning the Study of Geothermalism and the Thermalization Process of Underground Waters in Romania. Rcv. Roum. Geol., Geophys. Geogr., Serie Geologie, Bucharest. Institutul Geologic al României 25 HYDROGEOTHEHMAL STRUCTURES IN ROMANIA 193 A 1 i-M e h m c d E., Ba ndra b u r T., Crăciun P„ Gh en ea C., P o 1 o n i c P., Visarion M. (1978) Contributions to the Knowledge of Structures with Thermal Waters in the Eastern Part of the Pannonian Depression (Romania). Proceedings of the Budapest Conference IAH-IAHS. Annal. Inst. Geol. Hung., LIX, 1 — 4, 431 — 448, Budapest. Ba ndra b tir T., Crăciun P., (1975) Considârations sur la conimposition chimique et gazeuse des eaux thermales de la pârtie orientale de la Depression Pannonique (Rou- manie). Asoc. Internat. Sc. Hydrologiques, Symposium de Grenoble. BoldijsarT. (1965) Terrestrial I-Ieat and Geotherinal Resources in Hungary. Bull. Simp. Voie., 1965, New Zealand. Crăciun P., Bandrabur T. (1976) Some Geothermal Aspects of the Deep-Seated Aquifer Systems in the Getic Depression. Internat. Congr. on Thermal waters. Geo- thermal Energy and volcanism on the Mediterranean Arca. Athens. F e r u M. (1970) Apele termale din partea de vest a Dobrogei centrale și posibilitățile de valo- rificare a acestora. Inst. geol. St. tehn. econ., E-9, 79—84. București. G o 1 i ță N a t a 1 i a, G o 1 i ț ă E. (1980) Condițiile hidrogeologice ale zăcămîntului de ape minerale din zona Călimănești-Cozia St. tehn. econ., E-14, București. L ițea nu E., Va sil eseu G., Opran C. (1965) Fundamentarea cercetărilor hidro- geologice pentru descoperirea de noi surse de ape hipertermale în Cîmpia de Vest a țării. D.S. Inst. geol-, LI/2, 82 — 102, București. N e g o 1 ță V. (1970) Etude sur la distribution des temperatures en Roumanie. Rev. Rotim. Geol. Giophys., Geogr., Scrie Geophysique, 14, Bucarest. Opran C. (1974) Apele termale din România. Șt. și tehn., 3, București. Pa raschiv D., Cristian A. (1976) Cu privire Ia regimul geotermic al unităților struc- turale pentru hidrocabruri din România. St. cerc, geol., geofiz., geogr., seria Geol., 1, București. Pa seu M. (1965) Considerații asupra originii apelor termale din România. Congr. VII, Asoc. Carp.-Balc. Sofia. Pricăjan A. (1972) Apele minerale și termale din România. Ed. tehn., București. R ă d u 1 e s c u D., C o r n e a I., Săndulescu M., Constantinescu P., R ă d u- 1 e s c u F., Pompilian Al. (1976) Structure de la croute terrestre en Roumanie. An. Inst. geol., geofiz., L, 5 — 36, București. S 1 ă v oa că D. (1971) Geneza apelor minerale de la Tușnad. Inst. geol. SI. tehn. econ., E-9, 95 — 102, București. SlăvoacăD., G o 1 i ț ă N„ Geamă nu V cronica, Lupii P., S im ion G. (1977) Considerații hidrogeologice asupra ivirilor naturale cu ape termale din România. Inst. geol. geofiz. St. tehn. econ., E-13, București. V a s I 1 e s c u G., N e c h i t i G. (1968)Contribuții la cunoașterea geologică și hidrogeologică a zonei orașului Oradea. Bul. Soc. șt. geol. R.S.R. X, 291 — 308, București. Va sil eseu G., Nechiti G. (1970) Cercetări hidrogeologice în zona stațiunilor bal- neare Felix și 1 Mai. Inst. geol. St. tehn. econ., E-8, 115—132, București. V a s i 1 e s c u G., O p r a n C. (1975) Remarques concernant les structures â eaux thermales en Roumanie. Inst. geol. geofiz., St. tehn. econ., E-12, 155 — 161, București. Vel ic iu S. (1971) Contribuții geoterinice la cunoașterea hidrogeologică a zonelor Vața de Jos. Felix și 1 Mai, Herculane. Lucrările Simpozionului de ape minerale. — (1975) Contribuții la cunoașterea terinalismului din sudul Munților Apuseni și bazinul Streiului. St. cerc, geol-, geofiz., 14, 2, București. 13 — cg 658 Institutul Geologic al României Institutul Geologic al României ZONES, SOUS-ZONES ET ENSEMBLES CARACTERISTIQUES DE CALPIONELLIDAE TITHONIQUE-NROCOMIENNES1 PAR GRIGORE POP2 Calpionellidae. Tithonian. Valanginian. Microfauna zonation Microțauna assemblages Tethys. Bioslratigraphic scheme. Abstract. T i t h o n i a n-V a 1 a n g i n i a n Calpionellid Zones, Sub zones and Characteristic Assemblages. In this paper, it is admitted that the Calpionellid standard zones of the western Mediterranean province have a global value (Tethys area) for the corresponding Upper Tithonian-Valanginian interval. The zone sare subdivided into subzones or intervals bearing some characteristic asseinblages, as follows : Crassicollaria zone with Cr. intermedia and Cr. brevis assemblages, Calpionella zone including C. alpina, Remaniella and C. elliptica subzones, Calpionellopsis zone wilh Cs. simplex, Cs. oblonga and Lorenzlella assem- blages, Calpionellites zone with Ct.darderi and T. carpatica assemblages. The Tithonian/ Berriasian boundary is situated near the limit between C. alpina and Remaniella subzones represented by the first occurrence of Remaniella. Les resultats remarquables acquis en ce qui concerne la taxonomic et la rdpartition stratigraphique des Calpionellidae permettent actuelle- ment une datation assez detaillee des formations tithonique-ndocomiennes d’origine pâlagique du domaine tdthysien. Grâce â cela, la valeur biochronologique de ce groupe de micro- organismes planctoniques y est tout ă fait particuliere. En effet, les Calpio- neilidae peuvent faciliter la correlation plausible de telles formations situees dans des regions tres eloignees les unes des autres. Definies d’abord dans l’aire de la Mediterran^e occidentale par A 11 e m a n n et al. (1971), les zones standard ont etd reconnues ensuite 1 Note recue le 4 avril, 1980 et acceptâe pour publication le 8 mai, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. ICR. Institutul Geologic al României 196 GR. POP dans les Carpathes occidentales (Borza, 1974), les Carpathes m6ridio- nales etan Cuba (Pop, 1974, 1976). D’ailleurs, la plupart des auteurs s’accordent pour admettre que cette zonation est tres vraisemblablement applicable dans d’autres r^gions (Balkans, Moyen Orient, Caucase, Tibet, Mexique, Venezuela). De plus, il existe des donnees qui permettent la separation des sous- zones et des ensembles de Calpionellidae caractârisant des intervalles plus limites. Dans cette note, l’auteur presente ses conclusions concernant les possibilites actuelles de subdivision et d’extension des zones standard â l’^chelle globale â partir des donnees existentes. Prineipes utilises La subdivision des zones s’appuie sur plusieurs criteres d’importance differente, mais lies notamment â l’dvolution phylog^nique des Calpionel- lidae : — la premiere apparition des genres ou des especes qui repr^sente un ev^nement irreversible; — la variation et la diversification des aspects morphologiques des especes; — l’association d’une maniere ou d’autre des especes qui consti- tuent en effet le contenu faunique des intervalles stratigraphiques ; — la fr^quence relative des especes. Mais elle semble etre plus facilement influenc6e d’une part par les facteurs ecologiques et d’autre part par les conditions de conservation (diagenetiques). Malgr6 cela, cer- taines especes montrent presque constamment leur proliferation dans le cadre d’un intervalle donnd. Des variations de la frâquence des especes sont connues meme dans l’aire d’un seul bassin. L’utilisation stratigraphique des Calpionellida doit tenir compte egalement qu’elles apparaissent dans les formations calcaires et marneuses p61agiques dont les sediments se sont accumules dans des bassins geo- synclinaux (sillons) en dessus de la limite „CCD”, principalement sur leurs pentes et hauts-fonds, et rarement dans des bassins assez larges, de profondeur mod6ree, situes sur les plates-formes (pârtie centrale de la plate-forme moesienne, par exemple). La genese des sediments â Calpionellidae dans les sillons surtout est souvent controlee par des phenomenes de resedimentation et de glissements sous-marins qui peuvent donner des sequences plus ou moins developpees montrant des lacunes stratigraphiques. D’autre part, les hauts-fonds (swells) comportent g6ndralement des sequences condensdes ou l’extension verticale de certains intervalles peut etre tres limitee. Des differences biogeographiques sont signaldes. Elles s’expriment particulierement par l’appauvrissement de certaines especes — par exem- ple Calpionella elliptica dans l’aire vocontienne et au Cuba. Typiquement mesogeenes, les Calpionellidae peuvent montrer normalement des varia- tions vers les limites du domaine. Institutul Geologic al României 3 ZONATION DES CALPIONELLIDAE 197 Zones standard, sous-zones et ensembles caraeteristiques de Calpionellidae A la suite des etudes approfondies portees sur la valeur stratigraphi- que des Calpionellidae dans differentes regions du domaine mesogeen, actuellement on peut admettre non seulement le fait que les zones standard (Crassicollaria, Calpionella, Calpionellopsis, Calpionellites) sont valables, mais aussi qu’elles sont applicables a l’dchelle globale. En outre, dans la zone â Calpionella, on peut definii- trois sous-zones (C. alpina, Remaniella, C. elliptica) (Fig. 1). Dans les autres zones, il est possible de distinguer des intervalles differents, caractdrises par ensembles de Calpionellidae. Une telle subdi- vision ne comporte pas de limites nettement etablies et par consequent est moins precise que la sous-zonation. Les precisions ulterieures seront donc â remplacer eventuellement les ensembles par sous-zones. La subdivision et l’extension â l’âchelle globale des zones standard ont ete possibles grâce aux etudes effectuees jusqu’â present, particuliere- ment â celles â caractere syst6matique concernant la distribution strati- graphique des Calpionellidae et leur correlation avec la faune d’ammo- nites (D o b e n , 1963 ; Boiler, 1963 ; Remane, 1963, 1969, 1971, 1974 ; C o 1 o m , 1965 ; Catalano, 1965 ; G e e 1, 1966 ; B a r t h e 1 et al., 1966 ; Le H e g a r a t et Remane, 1968 ;B orza 1969, 1974 ; A 11 e m a n n, 1971; A 11 e m a n n et al., 1971; Cata- lano et L ig ou r i, 1971; Far es et L a 8ni er, 1971; K r e i s e 1 et F u r r a z o I a - B er mu d e z , 1971; Le H egar a t, 1973 ; Fu r- r a z o 1 a - B e r m u d e z et Kreisel, 1973; Pop, 1974a, 1976; A 11 e m a n n et al., 1975 ; on et autres). Zone ă Crassicollaria. Le ddbut de cette zone est marque par la premiere apparition des Crassicollaria, Tintinnopsella et (ou) Calpionella. Elle s’etend jusqu’â la base de la zone suivante, correspondant ainsi au Tithonique superieur (zone â Transitorins, SE de la France). Des tentatives ont eu lieu pour subdiviser la zone (Remane, 1963 ; P o p , 1974a), mais les donnees existentes ne permettent pas encore leur generalisation â l’âchelle globale. C’est pom- cette raison qu’il est plus indique de separer seulement deux ensembles, l’un inferieur â Crassicollaria intermedia et l’autre superieur â Crassicollaria brevis. La limite entre les deux ensembles correspond â la diversification maximale du genre Crassicollaria et se situe un peu plus bas que le niveau median de la zone. Ensemble ă Crassicollaria intermedia — espece dominante dans la pârtie inferieure de la zone. Association: Crassicollaria massutiniana, Cr. parvula, Cr. brevis (tres rares â frequentes), Calpionella alpina (tres rare â rare) et depetites formes de Tintinnopsella carpatica (T. remanei) (tres rare â rare). Ensemble ă Crassicollaria brevis, dans lequel cette espece montre sa proliferation maximale sans atteindre toutefois la predo- minance sur les autres especes du genre Crassicollaria (sauf Cr. colomi). Institutul Geological României 198 GR. POP 4 ETAGES ZONES STANDARD SOUS- ZONES ENSEMBLE A: EVENIMENTS STRATIGRAPHIQUES BERRIASIEN VALANGINIEN Calpio ne 1 h t e s T. carpatica Ct. darderi Dernieres Calpionellidae BONET. \ ApparUion. de. ( alpionell Ues \ ApparUion de Calpionellopsis £ ApparUion de C. elliptica. (typique) ApparUion. de Remaniella ' H ExplosionC et oariation. morphologique K de C. alpina Premieres Crassicollaria Tintinnopsella, / C al pioneUa Calpionellopsis Lorenziella Cs. oblonga Cs. simplex Calpionella C. elliptica Rema - ni el la TITHONLQUE SUPERIEUR C. alpina Crassicollaria Cr. brevis Cr. intermedia Fig 1 — Zones, sous-zones et ensemble® caractâristiques de Calpionellidae dans le do- maine m6sog6en. Association: Crassicollaria massutiniana et Cr. parvula sont abon- dantes. Calpionella alpina est legerement plus frequente que dans l’inter- valle precedent tandis que Tintinnopsella carpatica y persiste de la meme fagon. L’apparition de Crassicollaria colomi (rare ă, tres rare) dans cet intervalle semble etre intâressante, de sorte qu’elle pourrait fournir des renseignements stratigraphiques pr4cieux. 5 ZONATION DES CALPIONELLIDAE 199 Zone ă Calpionella. Cette zone est definie par „l’explosion” et la diversification morphologique de Calpionella alpina. Elle est rapportee au Tithonique superieur (zone ă Jacobi) et au Berriasien inferieur-moyen (zones â Grandis-Occitanicus ou ă Euxina-Privasensis) dans le SE de la France et le Subbetique (Espagne) (Le H e g a r a t et R e m a ne , 1968 ; Le Hegar a t, 1973 ; Allemannet al., 1975). Trois sous-zones y peuvent etre separees sans trop de difficulte, c’est-â-dire â C. alpina, â Remaniella et ă C. elliptica. S o u s - z o n e a Calpionella alpina, delhnitee par la limite inferieure de la zone et l’apparition de Remaniella. Elle represente ainsi le Tithonique terminal (zone ă Jacobi) et eventuellement le Berria- sien basal (zone â Grandis, pro parte). Association : Calpionella alpina heterogene (formes grandes et „moyennes”) et nettement prevalente, Crassicollaria parvula (frequente ă> abondante), Cr. massutiniana (frequente a rare), Cr. brevis (rare â tres rare), Cr. intermedia (rare ă tres rare), Cr. colomi (tres rare) persistant seulement dans la pârtie basale et petites formes de Tintinnopsella carpa- tica (rare â tres rare). II est â noter l’appauvrissement progressif, parfois brutal, de certai- nes especes du genre Crassicollaria (Cr. intermedia et Cr. brevis surtout) dans le cadre de cette sous-zone. Sous -zone a Remaniella marquee par l’apparition de ce genre et la limite de la sous-zone suivante. Elle correspond generalement au Berriasien inferieur. II s’agit en effet d’un evenement phylogenique important montrant le dâbut des Calpionellidae â col compose. De plus, il est situe probable- ment dans la zone â Grandis tout preș de la limite classique Tithonique/ Berriasien et, par consequent, Jurassique/CretacA Bien que les represen- tants du genre Remaniella soient rares ă ce niveau, ils ont âte remarques dans presque toutes les sequences systematiquement etudiees (R eman e, 1963, 1969 ; D o b e n , 1963 ; Boiler, 1963 ; Le H 6 g a r a t et Remane, 1968 ; Catalano et L i g o u r i, 1971; Borza, 1969 ; P op, 1974a, 1976 ; A 11 e m a n n et al., 1975 ; et autres). Association : Calpionella alpina plus heterogene et toujours abon- dante (formes grandes, „moyennes”, petites, allongees) accompagnee de formes intermediaires C. alpina/C. elliptica notamment dans la pârtie superieure de la sous-zone, petites formes de Crassicollaria parvula souvent frequente, tres rares Cr. massutiniana, parfois Cr. intermedia et Cr. brevis (pârtie basale) et petites ă moyennes Tintinnopsella carpatica, Remaniella cadischiana, R. dadayi, R. ferasini (rares â tres rares). Sous-zone a Calpionella elliptica, definiepar l’appa- rition des formes typiques de cette espece coincidant souvent avec l’aug- mentation notable" de sa frequence et la limite superieure de la zone. Elle correspond generalement au Berriasien moyen. Dans certaines regions (SE de la France, Cuba), les coupes etudiees montrent que Calpionella elliptica est assez rare, de sorte que son appa- rition est difficile â preciser mais toutefois reconnaissable. Dans ce cas, Institutul Geological României IGR/ 200 GR. POP 6 on peut utiliser des criteres supplementaires. A ce niveau, TintinnopseUa carpatica, est repr^sentee par des formes „moyennes” frequentes et peu apres par de grands exemplaires, typiques. En meme temps, il est â noter l’apparition des formes intermediaires T. carpatica/T. longa et de T. longa. Le genre Lorenziella peut apparaître dans la pârtie superieure de la sous-zone. Association : Calpionella elliptica dont la frequence est assez varia- ble, petites formes spheriques, souvent abondantes de C. alpina, Tintin- nopsella carpatica montrant une proliferation graduelle mais marquante, T. longa et formes de passage T. carpatica/ T. longa (rares), Remaniella cadischiana, R. dadayi (rares), Lorenziella plicata (tres rare), et petites formes de Crassicollaria parvula (trăs rare). Zone ă Calpionellopsis. Elle comporte des limites tres facile â recon- naitre, respectivement les apparitions des genres Calpionellopsis et Calpio- nellites. Cette zone comprend le Berriasien superieur et la pârtie basale du Valanginien. Bien qu’elle soit tres riche en espece de Calpionellidae, sa sous- zonation demeure encore delicate. En consequence, il est raisonnable de recourir â une datation plus relative fondee sur des ensembles de micro- faune. C’est ainsi que l’on peut separer trois intervalles successifs et ine- gaux correspondant generalement aux sous-zones de E e m a n e (1969). En semble d Calpionellopsis simplex qui caracte- rise la pârtie inferieure de la zone. Association: Calpionellopsis simplex (frâquent â abondant), for- mes intermediaires Cs. simplex/Cs. oblonga (rares), TintinnopseUa carpatica (frequente ă abondante), T. longa (rare), Remaniella cadischiana, R. dadayi (rares), Lorenziella plicata, L. hungarica (tres rares), petites for- mes de Calpionella alpina (rare), Remaniella cadischiana, R. dadayi (rares), Lorenziella plicata, L. hungarica (tres rares), petites formes de Calpionella alpina (rare) et parfois tres rares C. elliptica et Crassicollaria parvula dans la pârtie inferieure de l’intervalle ou elles disparaissent. Ensemble a Calpionellopsis oblonga montrant un iutervalle plus large marque par l’apparition et la proliferation de cette espece. Association : on remarque l’abondance de Calpionellopsis oblonga, la diminution de la frequence de Cs. simplex et l’apparition sporadique (RAmphorellina subacuta. Les autres especes rencontrees dans l’intervalle precedent persistent de la meme fa§on et ne semblent montrer aucun ele- ment nouveau. Ensemble â Lorenziella situe dans la pârtie superieure de la zone ou ce genre devient plus frequent. Le geme Remaniella (E. dadayi surtout) parait atteindre Egalement son apogde (frequent â abon- dent). Association : Lorenziella plicata et L. hungarica (frequentes), Rema- niella dadayi et R. cadischiana (frequentes â abondantes), TintinnopseUa Institutul Geological României \jGRy 7 ZONATION DES CAEPIONELLIDAE 201 carpatica toujours predominante, T. longa (frequente), Calpionellopsis oblonga (frequente â rare), Cs. simplex (frequent â, rare, parfois absent). Dans cet intervalle, on remarque l’extinction de Calpionella alpina. Zone ă Calpionellites. La derniere zone est delimitee par l’apparition du genre Calpionellites et la disparition de la familie Calpionellidae B one t et correspond generalement au Valanginien (sauf sa pârtie basale). Dans cette zone on peut distinguer deux ensembles fauniques, l’un inferieur plus large (parties inferieure et moyenne) â Calpionellites darderi et l’autre superieur plus restreint â Tintinnopsella carpatica. E n s emble a Calpionellites darderi caractdrise par la presence de cette espdce. Association : Calpionellites darderi dont la frequence est extremement variable, Ct. uncinatus, Ct. murgeanui, Ct. caravacaensis (frequents â tres rares) et la plupart des especes de l’ensemble precedent qui montrent une diminution graduelle mais importante de leur frequence ('Tintinnopsella longa, Lorenziella plicata, L. hungarica, Remaniella dadayi, R. cadischiana, Amphorellina subacuta, parfois Calpionellopsis oblonga). Seule Tintinnop- sella carpatica persiste de fagon frequente. Lorsqu’il est present, Calpio- nellopsis simplex est toujours tres rare et ne d^passe guere la pârtie basale de l’intervalle. Ensemble ă Tintinnopsella carpatica caracterise par l’appauvrissement notable des Calpionellidae et l’absence des Calpio- nellites darderi, de sorte que c’est souvent la seule espece qui persiste. Son extinction marque en effet la disparition de la familie entiere des Calpio- nellidae. Dans cet intervalle, T. carpatica est accompagnee quelquefois par T. longa et (ou) Remaniella (tres rares). La distribution stratigraphique des especes de Calpionellites plus râcemment etablies {Ct. murgeanui P o p et Ct. caravacaensis A 11 e - mann) (Pop, 1974b; Allemann, Trejo, 1975) reste â etre piAcisee. A l’issue de cette presentation synthetique, on peut formulei' quel- ques remarques d’ordre general. Si l’on tient compte de la nature planctonique des Calpionellidae, de leur repartition verticale semblable dans differentes regions mesogeen- nes et egalement de l’absence des especes endemiques, il resulte la valeur globale de la zonation basee sur ce groupe de microorganismes. La tecto- nique globale constitue un critere supplementaire qui montre que cette interpretation est d’autant plus valable. En consequence, les Calpionellidae permettent actuellement la datation d6taillee des formations calcaires pelagiques. Le schema biochronologique propose represente un modele ouvert, susceptible d’etre ameliore. Dans ce but, l’evolution morphologique des Calpionellidae et la distribution des especes plus rares sont â prendre en consideration. Enfin, la signification stratigraphique de certaines limites de la zonation reste encore ă precisei. M Institutul Geological României \ igr/ 202 GR. POP 8 BIBLIO GRAPHIE Allemann F. (1970) Berriasian Calpionellids in Southern Spain. Abs. II Plankt, Conf., 1970, Rome. — T r e j o M (1975) Two New Spe:ies of Calpionellites irom the Valnnginian of Mexico and Spain. Eclogae geol. Hei»., 68/2, 457 — 460, Basic. — Giiin W., Wiedmann J. (1975) The Berriasian of Caravaca (Prof. of Murcia) in the Subbetic Zone of Spain and its Importance for Defining this Stage and the Jurassic-Cretaceous Boundary. Colloque sur la limite Jurassique-Cretace, (Lyon,Neu- châtel, 1973.) Mem. B.R.G.M., 86, 3-11, Paris. — Catalano R., Fares F., R emane J. (1971) Standard Calpioneliid Zonation (Upper Tithonian-Valanginian) of the Western Mediterranean Province. Proc. II Plankt. Conf., Rome 1970, II, 1337 — 1340, Ediz. Tecnoscienza, Rome. B a r t h e 1 K. W., C e d i e 1 F., G e y e r O. F., R e m a n e J. (1966) Der subbetische Jura von Cehegin (Provinz. Murcia, Spanien). Mitt. Bager. Staalssamml. Palăont. hist. Geol., 6, 167—211, Miinchen. Boiler K. (1963) Slratigraphische und mikropalaontologische untersuchungen im Neocom der Klippendecke (ostlich der Rhone). Eclogae geol. Helv., 56, 1, 15 — 102, Basel. Bonet F (1956) Zonificacion microfaunistica de las calizas cretacicas del Este de Mexico. Bol. Assoc. Mexic. Geol Petrol., VIII, 7—8, 389—488, XX Congr. Int., Mexico. Borza K. (1969) Die Mikrofazies und Mikrofossiiien des Oberjuras und der Unterkreide Klippenzone des Westkarpaten. Slotvak. Acad. Wissensch., 301, Bratislava. — (1974) Die slratigraphische Verwendung von Calpionelliden in des Westkarpaten. Proc. X Congr. Carp.-Balk. Geol. Assoc., Seclion I, 31 — 34, Bratislava. Catalano R. (1965) Calpionella di Calabianca (Castellaminare, Sicilia). Atti Soc. Tosc. Sc. Nat., A, LXXII, 3-26, Pisa. — L i g o u r i V. (1971) Facies a calpionelle della Sicilia occidentale. Proc. II Plankt. Conf., Roma 1970, I, 167—210, Roma. C o l-om G. ('965) Essais sur la biologie, la distribulion geographique et stratigraphique des Tintinnoidiens fossiles. Eclogae geol. Helv., 58, 1, 319—334, Bale. D oben K. (1963) Uber Calpionelliden an der Jura/Kreide-Grenze. Mitt. Bager. Staalssamml. Palăont. hist. Geol-, 3, 35—50, Miinchen. Far.es F. et Lasnier J. (1971) Le'Tintinnoîdi'ms fossiies, leur position stratigraphique et leur repartition en Algerie du Nor i. Proc. II P'ankl. Conf., Roma 1970, I, 539—554, Ediz. Tecnoscienza, Roma. F u r r a z o 1 a-B e r m u d e z G. et KreiselK. (19731 Los Tintinidos fossiles en Cuba. R. Tecnologica, 1/73, 27—45, La Habana. K r e i s e 1 K., Fu r ra z o 1 a-B er mu d e z G. (1971) Notas preliminares sobre la distri- bucion de Tinlinoids en Cuba. Minist. Min. Comb. Met. Dept. Geol., Publ. Esp., 4, 24 p., La Habana. Le Hegarat G. (1973) Le Berriasien du Sud-Est de la France. Thise, 576 p., Lyon. — Remane J. (1968) Tithonique superieur et Berriasien de la bordure cevenole. Corre- lation des Ammonites et des Calpionelles. Geobios, 1, 7 — 70, Lyon. Pop Gr. (1974a) Les zones de Calpionellides tithonique-valanginiennes du sillon de Reșița (Carpates meridionales). Rev. roum. geol-, geophgs., geoar. Geologi', 18, 109 — 125, Bnca'est. — (1974b) Une nouvelle espdce neocomienne de calpionellides. Rev. roum. geol.,geophgs., geogr., Geologie, 18, 105—107, Bucarest. 9 ZONATION DES CADPIONELLTDAE 203 — (1976) Ti l h o n i a n-Valaoginian Calpionellid Zones from Cuba. D.S. Inși. geol. geofiz., LXII (1974-1975), 237-266, București. Remane J. (1963) Les Calpionelles dans les couches de passage jurassique-cr6tace de la fosse vocontienne. Trav. Lab. Geol. Grenoble, 39, 25 — 82, Grenoble. — (1969) Les possibilites actuelles pour une ulilisation des Calpionelles (Protozoa incertae sedis, Liliata?). Proc. I Plankt. Conf., Geneva 1967, II, 559—573, Leiden. — (1971) Les Calpionelles, protozoaries planctoniques des mers mesogeennes de l’6poque secondaire. Annal. Guibhard, 47-e an., 1—25, Neuchâtel. — (1974) Les Calpionelles. Cours de IlI-e cycle, Paleont. II, Univ. Geneve, 58 p., Geneve Trcj o M. (1975) Tintinidos mesozoicos de Mexico (Taxonomia y datos paleobiologicos). Bol. Asoc. Mexic. Geol. Petrol., XXVIII, 10—12, 329 — 449, Mexico. Institutul Geological României Institutul Geologic al României Projet 25: Stratigraphic Corelation of the Tethys-Paratethys CHATTIAN - BADENIAN BIOCHRONOLOGY IN ROMANIA BY MEANS OF MOLLUSCS1 BY VICTOR MOISESCU, GHEORGHE POPESCU 2 Chatiian-Badenian. Mollusca. Biochronology. Paratethys. Biozones. Stratigraphic distri- bution ; Bomania. Sommaire Bioehronologie de l’intervalle Ch a 11 i en-B a d 6 n i e n deRou- m a ni e concernant les m ollu s qu es. Tenant compte de l’evolution des associa- tions de mollusques dans la region roumalne de la Paratethys Centrale on a s6par6 les bio- zones suivantes; Congeria basteroti-'Micromenetus tamassensis, Costatoleda prannnobiaetor- mis, Crassostrea gryphoides aginensis, Chlamys gigas, Parvamussium duodecimlamellaturn Pecten hornensis, Pecten beudanti strictocostata, Neopycnodonte navicularis/Clio falauxi, Chlamys latissima nodosiformis, Amussium denudatum et Chlamys wolfi/Chlamys scissa wulkae. Chaque biozone est definie par ses limites — inf6rieure et superieure — sous le rapport de la distribution stratigraphique des mollusques de Roumanie. Pour ce travail on a utilis6 tous les resultats des etudes personnelles, ainsi que ceux des autres auteurs ; ces rdsultats ont 6t6 correles avec les zones de plancton et de nannoplancton. Several works and disscusions occasioned by various International congresses, particularly the 7th Congress on Mediterranean Neogene, have focused upon the Tertiary deposits in general and especially upon the Neogene ones. A few biochronological zonations are known so far, based on nan- noplankton, planktonic and benthonic foraminifera, nummulites, ostra- cods and other groups of fossil micro- and macroorganisms. As much as 1 Paper received on February 13, 1980 and accepted for publication on February 18, 1980. 2 Institutul de geologie și geofizică, str. Caransebeș 1, 78344, București. Institutul Geological României 206 V. MOISESCU. G. POPESCU possible all groups of organisms (the molluscs included) are taken in the biozonation schemes that are correlated with the radiometric data and the paleomagnetic epochs. As far as the molluscs are concerned, it was attempted to establish their biostratigraphic value (Demarcq, 1979 a-c; Catzigras, 1979 ; Feneix, 1979'; Kr ach, 1979 a-c ; R u s u , 1979 a-b ; 8 ta n- cu, 1979, etc). Biozonation schemes (B â 1 d i, 1975 ; B â 1 di & 8 en e s , 1975 ; D emarc q, 1979 b) were worked out, especially based on pectini- ds. In the present paper we shall attempt to make a biozonation by means of molluscs, for the Chattian-Badenian interval in Romania, taking into account especially the pectinids and the ostreides. For the Chattian, considering the multitude of limnic, brackish-water and very rarely marine facies, very often passing gradually to one another, we shall take into account other forms of molluscs as well. It is worth remembering that B â 1 d i (1975) alone and in coopera- tion with S e n e s (1975) established for the above 'mentioned interval the following biozones : Chlamys picta, Chlamys decussata, Flabellipecten carryensis, Chlamys gigas, Chlamys herrmanseni, Flabellipecten passinii, Flabellipecten besseri and Chlamys elini. Analysing all these biozonation schemes, the Chattian-Badenian mollusc assemblages from Romania, as well as their range in the Para- tethys, we have established a sequence of biozones as shown in Table 1. 1. Congeria basteroti — Mieromenetus tamassensis Zone Locus typicus : Tămașa, valea Petrindului, north-east Transylvanian basin (Mo is eseu, 1972, 1975, 1978a, 1978b). Stratum typicum: Dîncu-Tămașa beds. Occurrence : Cluj-Napoca, Dealul Cetățuia ; Sînpaul, Valea Sînpaului; Cernești, Valea Corneștilor ; Dineu and Arghișu, Valea Almașului basin all of them in the north-west of Transylvania (M o i s e s c u , 1972, 1975, 1978a, 1978b). Definition. The base of the zone is marked by the appearance of the index species, Congeria basteroti Desh.in L a mar c k and Micro- menetus tamassensis M o i s e s c u , as well as of the species : Pnio wolfi wolffi M o d e 11 , U. wolffi transsylvanicum Moisescu, U. modelli M oi s eseu , Vanderschaliea holassii boeckhi M o d e 11 , Cerastoderma concameratum H 61 z 1, Polymesoda (Pseudocyrena) convexa maxima Ho 1 z 1, P. (P.) convexa costulata (C o s s m a n n & P e y r o t), Lentidium solcolovi subtriangulum Moisescu, Theodoxus (Vittocli- thon) arghissensis Moisescu, Brotia (Tinnyea) escheri grossecostata (K1 e i n), B. (T.) escheri bicincta S a n d b e r g e r , Pachychilus (Oxy- melania) tenuistriatum Moisescu, P. (Pseudopotamis) transsylva- nica Moisescu, Melanopsis (Lyrcaea ) impressa haniheni H o f m a n n The upper boundary is marked by the occurrence of the species Costatoleda psammobiaeformis. Institutul Geologic al României 16 3 CHATTIAN-BADENIAN BIO’CHRONOtLOGY IN ROMANIA 207 C har ader istics. The biozone is placed at the upper part of the Rupelian and the lowermost part of the Chattian stage, corresponding to the nannoplankton zone NP24. In the Dîncu-Tămașa beds only a rewor- ked nannoplankton assemblage from the Cretaceous has been found so far. We mention that from the Cetate beds underlain by the Dîncu-Tămașa beds, Mdszâros et al. (1975) identified the nannoplancton zone NP24. Both lithostratigraphic units belong to the same biostratigraphic unit, Congeria basteroti/Micromenetus tamassensis Zone. Remarks. The biozone' contains in its lower part (i.e. in the Dîncu- Tămașa beds) a polytypical, mainly fresh-water assemblage with a redu- ced number of oligo-miohaline elements. Towards the upper part (in the sandstone formation of the Cetate beds) it has a brackish-water, mio-plioha- line aspect. In the zonal assemblage at this level the limnic species belonging to the genera Unio, Vanderschaliea and Theodoxus are missing ; there are other species that belong to the two lithostratigraphic units and two subspecies — Lenticorbxda helmerseni transsylvanica (M o i s e s e u) and Janschinella gardzkii tenuitesta M o i s e s c u occur only in the Cetate beds. It is obvious that most elements of the biozonal assemblage are endemic. In the lower and middle part of the biozone in the Jibou-Ileanda area (i.e. in the Ileanda beds) a peculiar assemblage has been found, that has neither the two index taxa nor the most important species that accompany it, that is Janschinella vinogrodskii Merklin, Car diurn s&rogosicum Noss. and Cardium lipoldi Rolle (Rusu, 1977); it is a mio-pliohaline, oligotypical assemblage. In the upper part of this biozone (i.e. in the Vai’ Sandstone) there are only a few brackish water mollusc species belonging to the genera Polymesoda and Congeria. Farther on, in the Ileanda-Poiana Blenchii area there is a local zonal assemblage, represented by the so called “Pycnodonte callifera level” (Ru s u , 1977). It contains species of Pycno- donte callifera (L a m k .), Callista splendida (Marian in D e s h a y e s), C. beyrichi (Se mp.), Pelecyora (Cordiopsis) westendorpi (N y s t), P. (C.) boehmi (H 6 1 z 1 ), Arctica islandica rotundata (A g a s s i z ), Glossus szibstransversus (d’ Orb .), Turritella venus (d’ Orb.) etc. and it forms a marine brachy-euhaline, oligotypical assemblage. The Congeria basteroti-Micromenetus tamassensis Zone seems to be correlated to the Chlamys picta biozone in Bâldi & Senes’s zona- tion (1975). In our country Chlamys picta and the main mollusc species accompanying it do not occur at any biostratigraphic level. Under such circumstances we cannot make use of this zone, since it is difficult to esta- blish its location. 2. Costatoleta psammobiaeformis Zone Locus tipicus :Tihău, Valea Rea, south-east of the Jibou town, north-west Transylvania (Ș u r a r u , 1969, 1970 ; Moiseseu, 1978a). • Institutul Geologic al României \JCRZ 208 V. MOISESCU, G. POPESCU 4 Stratum tipicum : Valea Almașului beds (the clayey-sandy horizon bearing coal, a stratigraphic equivalent of the upper Zimbor beds or of the Cubleșu beds 3. Occurrence: Zimbor, Valea Almașului basin, north-west of Tran- sylvania in the Cubleșu beds, described as faciostratotype of the Egerian (Șuraru, 1975); west of Poiana Blenchii, on Valea Runcului, north Transylvania, in the Buzaș beds, equally described as a faciostratotype of the Egerian stage (R u s u , 1975); Merișor (Hațeg basin), in the gritty- conglomeratic and clayey-sandy brick coloured deposits with lens of fresh-water limestones (Moisescu)4; Lonea, Petrila, Dîlja, Aninoasa, Vulcan-Paroșeni, Lupeni, Bărbăteni, Uricani, Hobiceni, Cîmpu lui Neag, all of them located in the Petroșani basin, in the horizon 2 (lower produc- tive one) and horizon 3, described as a faciostratotype of the Egerian (Mo is eseu, 1975; Moisescu et al., 1979); Valea Muereasca, in the Getic depression in the lower marly horizon also described as a facio- stratotype of the Egerian (Motaș & Moisescu, 1975). Definition. The base of the zone is marked by the appearance of the index species — Costatoleda psammobiaeformis (Both) — as well as of the species : Cardium egerense Roth, C. edule greseri May er in W o 1 f f , Lutraria sanna Basterot, L. latissima Deshayes, L. (Psammophila ) oblonga soror Mayer-Eymar, Glossus burdigalen sis (Desh .), Pelecyora (Cordiopsis) boehmi (H 6 1 z 1), Solenocurtus bas- teroti Des M o u 1 i n s , S. antiquatus miocenicum (C o s s m . & P e y - r o t), Turritella venus d ’ Or b ., Euthriofusus burdigalensis (Def r .), Aporrhais callosus Roth, Athleta ficulina (L a m a r c k). The upper boundary is shown by the occurrence of the species Crassostrea gryphoides aginensis. Characteristics. This zone is placed in the lower and middle parts of the Egerian and can be correlated with the N3/P22 zone (Globigerina ciperoensis ciperoensis) in B 1 o w ’ s zonation (1969); it corresponds to the nannoplankton zones NP24—NP25 and the base of the NN1 zone (M e s z â r o s et al., 1975). Remarks. The zonal assemblage has a marine brachy-euhaline charac- ter, with many stenohaline representatives belonging to the genera Aporrhais, Cassidaria, Lutraria, Glossus, Panopea ete. (Ș u r a r u, 1970b). The assemblage is polytypical. In the type place the molluscs only appear as pelomorphosed casts restricted to a sandy clay facies. In the Buzaș — Poiana Blenchii area the Costatoleda psammobiae formis zone contains a non-fossiliferous sequence that separates two fos- siliferous levels (Turritella and Thracia level and Euthriofusus burdi- 3 In lhe two biozones already mentioned there are still fossiliferous deposits with mollusc species of the zonal assemblage C. psammobiaeformis, i.e. the assemblage at the base of the Curăplac eds (= Lower Zimbor beds) in the surroundings of Sîngeorgiu de Mezes. , 4 Moisescu V. (MS) Contiibution â la connaissance de Ia faune de mollusques oligocfenes du calcaire d’eau douce de Merișor (Bassin de Ha(eg) — in prinț. Institutul Geological României 5 CHATTIAN-BADENIAN BIOCHRONOLOGY IN ROMANIA 209 galensis one) with local extension (Rusu, 1969, 1972, 1977). They contain different species of the zonal assemblage, the index species ap- pearing only at the upper level. The zonal assemblage is restricted to a shallow water sandy marine facies in the Buzaș beds (Ș u r a r u, 1969). They are generally marine, brachy-euhaline, oligotypical assemblages. The zonal assemblage in the Cluj-Zimbor region contains both mio- pliohaline species and brachyhaline ones. It is a polytypical assemblage with the prevailing species : Gobraeus protractus (M ave r-E y m a r), Congeria basteroti Desh. in L a m k., Polymesoda convexa (Brongn.), P. convexa brongniarti (B a s t e r o t), P. convexa “allongee” (C o s s m. & P e y r.), Hydrobia andreaei B o e 11 g e r in Degrange-Touzin, H. obtusa Sandb., M. (Lyrcaea) impressa hantkeni Hofmann, Pirenella plicata (B r u g u i e r e) and Tympanotonos margaritaceus (B r o c c h i). In the Merișor area (Hațeg basin) there occurs an assemblage of limnic gastropods that contains neither the index fossil nor the other species of molluscs of the Costatoleda psammobiaeformis zone : it is a very peculiar, atypical assemblage belonging to the Chattian (= Egerian par- tim). It is found in the fresh water limestones that appear as lens inter- bedded within the “lower gritty-conglomeratic and clayey sandy brick- coloured horizon”. This is a fresh water, oligotypical assemblage and it is made up of: Ferussina tricarinata (B r a u n), Coretus cormc cornu (B r o n g n i a r t), C. cornu solidus (T h o m a e), C.crassus (Serres), Cepaea rugulosa (Z i e t e n) and Pomatias antiquum (B r o n g n.). This assemblage is very different from the type assemblage of “psammobiaeformis” zone from the Transylvanian basin. The two horizons from the Petroșani basin (= lower productive horizon and gritty horizon) contain a zonal assemblage of miobrachy- haline molluscs similar to the one of the Cubleșu beds (in north-west Transylvania). The zonal assemblage from this basin has many non- fossiliferous sequences due to the repeated marine ingressions produced at relatively short intervals and that brought about disturbances in the paleoecological environment and in the sedimentation. Neither this assemblage nor the one from the Cubleșu beds, placed at the same stratigraphic level, contains the index species. In the “lower marly horizon” from the Valea Muereasca (Getic depression) there is another zonal assemblage without the index species (AI o t a ș, 1959 ; Mo t a ș&Mo is eseu, 1975). It is a marine brachy-euhaline polytypi- cal assemblage with some reworked material ; it comprises fauna! elements of the boreal bioprovince as well as Southern (mediterranean) elements; 50 percent of its species are also encountred in the holostratotype of the Egerian at Eger. The most representative species are : Turritella vemts d’O r b., T. venus margarethae Gaâl, Aporrhais callosus (Both), Ficopsis burdigalensis (Sowerby), Typhis (Lyrotyphis) cuniculosus (N y s t), Turricula (Surcula) anomala (Bel Iar di), Epalxis (Bathy- toma ) cataphracta (B r o c c h i). Institutul Geological României 210 V. MOISESCU, G. POPESCU 6 The Costatoleda psammobiaeformis assemblage contains a relati- vely small number of Oligocene ante-Chattian species (i.e. Crassostrea cyathula (L a m k.), P. convexa (Brongn.), Congeria aff. brardii (Brongn.), Callista spendida (Mer ian in Desh.), Glossus sub- transversus (d’Orb.), Arctica islandica rotundata (Agassiz), Pele- cyora (Cordiopsis) westendorpi (Nyst), Stenothyra pupa (Nyst), Stenothyrella lubricella (S a n d b.), Ampullinopsis crassatina (L a m k.) The Costatoleda psammobiaeformis zone can be correlated with the Chlamys decussata zone from Hungary and Czechoslovakia. In Ro- mania, Chlamys decussata (M ii n s t e r) does not occur at that biostra- tigraphical level becau.se of the mio-pliohaline facies. It appears in exchange in the Briozoan mari horizon, Priabonian in age from NW Transylvania at the level of the nannoplankton zone NP20—NP21 (Koch, 1894). Since Chl. decussata appears much lower, in the Priabonian, it has no lon- ger value as index fossil according to the aeception given by the two authors already mentioned. 3. Crassostrea gryphoides aginensis Zone Locus typicus Sînmihaiu Almașului at Dealu Cotului, north-west of Transylvania (Ș u r a r u, 1971; M o i s e s c u, 1972,1975,1978 a—b ; Busu, 1972). Stratum typicum : Dealu Cotului beds (= uppermost part of the Sînmihai beds), deseribed by Șuraru (1975) as a faciostratotype of the Egerian stage. Other occurrenees : Sînmihaiu Almașului-Dealul Colibele, Baica-Valea Băicuței, Zutor, Sîncraiu Al masului-Valea Sîncraiului, Topa-Mihăiești, Siliștea Nouă-Dealul Tifra, Lozna-Valea Loznei, all of them in north- west Transylvania (see : Șuraru, 1971; Rusu, 1972, 1977); Sălă- truc-Valea Sălătrucului, in the Petroșani basin (Răileanu, 1955; Voicu et al., 1976); Bahna and Balta Albă-Baia de Aramă region (M a c o v e i, 1909; M a r i n e s c u & M a r i n e s c u, 1962); Rusești, Răchita, Crivadia (Hațeg basin). Definition. The base of the biozone is marked by the appearance of the index species — Crassostrea gryphoides aginensis (T o u r n o u e r) — as well as of the species : Crassostrea gryphoides crassissima (L a - m a r k), C. gingensis (D e f r.) and Ostrea edulis lamellosa B r o c c h i. The upper boundary is delimited by the appearance of the zonal assemblage Chlamys gigas. Characteristics. This zone is placed in the base of the Aquitanian or the uppermost part of the Egerian and corresponds to the N4 zone (in B 1 o w’s Zonation, 1969) as well as to the lower part of the NN1 nanno- plankton zone. It can also be correlated with the Miogypsina gunteri zone, corresponding to the parastratotype of the Aquitanian in the Carry- Le Rouet section, France. Remarks. In the Transylvanian basin the zonal assemblage occurs as both a mo no typical assemblage being restricted to the “gritty-coal Institutul Geologic al României 7 CHATTIAN-BADENIAN BIOCHRONOLOGY IN ROMANIA 211 horizon” of the Valea Almașului beds, an equivalent of the Dealu Cotului beds in the Cluj-Sînmihaiu Almașului region (see Șuraru, 1970b) and as a polytypical assemblage in the Dealu Cotului beds. When it ap- pears as a polytypical assemblage, beside the above mentioned Ostrea, many species from the underlying biozone are added; it is a mio-plio- haline assemblage developed in an eulittoral-epineritic facies. In the Lozna region there occurs a marine brachy-euhaline oligotypical assemblage with the following species : Callista lilaeinoides S c h a f f e r, Glosus sub- transversus (d’O r b.) and Turritella venus d’O r b., etc;itwas described by R u s u (1972, 1977) from the “Callista lilaeinoides level”. This assem- blage seems to be placed at the same stratigraphic level with the Cras- sostrea gryphoides aginensis Zone. To the zonal assemblage from the Bahna basin, other marine brachy- euhaline species are added, such as: Cardita ( Cardiocardita ) partschi Goldf., Lingă columbella (Lamk.), Turritella tricarinata Brocchi, T. cathedralis Brongn., T. vermicularis Brocchi, T. turris B a s t., T. erronea Cossmann, Natica millepunctata Lamk., N. catena helicina (Brocchi), Architectonica simpler (Broun), Nassa haueri (Micht.), Dorsanum miocenicum (Micht.), Perrona jouanetti des- cendens (H i 1 b e r), etc. The Crassostrea gryphoides aginensis zone corresponds to the Flabel- lipecten carryensis zone in B â 1 d i and Sene s’s zonation. Due to the same thing, i.e. the brackish water character of the deposits, FI. car- ryensis does not appear in our country at this level or at any other one. Under these circumstances, since the characteristic zonal assemblage of the two authors’ zonation is not present, we have proposed as index fossil the species C. graphiodes aginensis. 4. Chlamys gigas Zone Locus typieus : Coruș, north-west Transylvania (R ă i 1 e a n u Oegulescu, 1964; R u s u, 1969; Mo is eseu, 1975, 1978 a—b; Culda&Moisescu, 1977). Stratum typicum : Coruș beds. Other improtant occurrences : Cluj-Napoca, in the places named Coasta cea Mare, Dealul Daiu, Hida, Baica, Tihău, Gîlgău Almașului, Brîglez, Cristolțel etc. all of them in north-west Transylvania (K o c h, 1900 ; R ă i 1 e a n u &Negulescu, 1964 ; R u s u, 1969, 1972, 1977 ; Mo i- s e s c u, 1972,1975,1978 a—b); Sălătruc-Valea Sălătrucului, in Petroșani basin (R ă i 1 e a n u, 1955 ; R ă i 1 e a n u et al., 1960; Răileanu& &Negulescu, 1964; C u 1 d a, 1972, 1975 ; Voi cu et al., 1976); east of Zalău town in Brebi-Nirșid area (Rusu, 1967); Brădet-Valea Brădetului, in Brădet beds (Z o 11 a, 1965); Borod basin in Valea Băiții, Mișca and Cetea (Ș u r a r u & Ș u r a r u, 1973). Definition. The base of this zone is delimited by the appearance of the index fossil Chlamys (Macrochlamys) gigas Schloth., as well as the species : Anadarafichteli (Desh.), A. fichteliplanata Schaffer, Institutul Geological României 212 V. MOISESCU, G. POPESCU 8 A. moltensis Mayer, Glycymeris fichteli (Desh.), G. pilosus deshayesi Mayer, Chlamys ( Macrochlamys ) solarium (Lamk.), C. (N.) hol- geri (Geinitz), Chl. (Aequipecten ) scabrella (L a m k.), Chl. multi- striata (Pol i), Pecten pseudobeudanti Deperet&Roman, P. pseu- dobeudanti rotundata S c h a f f e r, Acanthocardia saucatsense M a y e r, Rudicardium grande (Holzl), Laevicardium kubecki (Hauer), Pho- ladomya alpina rectidorsata H 6 r n e s, Natica epiglotina moldensis Schaffer. The upper limit is marked by the zonal assemblage Parvamussium duodecimlamellatum/Pecten hornensis. Characteristics. The biozone is placed at the top of the N4 zone and at the lower part of the N5 zone, or in the upper half of the nannoplank- ton NN1 zone respectively. It eorresponds to the Aquitanian (=Eggen- burgian). Remarks. The Chlamys gigas zone is the most typieal one of the Aquitanian of our country and generally of the Central Paratethys. The best represented zonal assemblages are found at Coruș (Tran- sylvanian basin) and at Sălătruc (Petroșani basin). In these two areas there occur both the index species and the most representative species such as: Anadara fichteli (Desh.), A. fichteli planata Schaffer, A. fichteli elongatior (S a c c o), A. diluvii pertransversa (S a c c o), Glycymeris fichteli (Desh.), G. pilosus deshayesi Mayer, Chlamys (Macrochlamys) solarium (L a m k.), Laevicardium kubecki (H a u e r) etc. In the Sylvanian basin, there is a region where the zonal assemblage does not contain the index fossil but contain several important species as: Pecten pseudobeudanti rotundata Dep. &Rom., Chl. (M.) sola- rium (Lamk.), Chl. (M.) holgeri (Geinizt), Acanthocardia saucat- sense (M a y e r) (R u s u, 1967). In the south-east of the Transylvanian basin, namely at Brădet (Persani) there is a poor atypical zonal assemblage made up of Chl. (Aequi- pecten ) scabrella (L a m k.), Chl. multi striatiis (P o 1 i), Lucina cf. fra- gilis (P h i 1.), Loripes dentatus (D e f r.). Both the index fossil and the most representative species are missing, except for Chlamys scabrella. The zonal assemblage at Brădet is extremely peculiar for the zonal assemblage Chlamys gigas. It has the same marine euhaline character, but is oligotypical. The mollusc assemblage described by Tot ta (1965) is placed at the lower part of the Brădet formation (in the N4—N5 zones). The Chlamys gigas zone assemblage from Coruș and Sălătruc and the one from Brădet are placed in different regions. Their synchronism is proved by the occurrence in all these areas of the benthonic foramini- fera Operculina complanata, Cribrononion dollfusi and Cribroelphidium onerosum, species that point out the zones N4—N5 (V o i c u et al., 1976). Another atypical zonal assemblage, this time a brackish water mio-pliohaline one, with brachy-euhaline influences is encountered in the Borod basin. Apart from the species of Nuculana notabilis Mayer, Institutul Geologic al României 16 9 CHATTIAN-BADENIAN BIOCHRONOLOGY IN ROMANȚA 213 Anadara moltensis elongata (Schaffer,) Cubitostrea frondosa De Serres, Lingă columbella (Lamk,), Turritella eryna d’Orb., T. eryna rotundata S c li a f f e r, T. turris taurolaevis S a c c o, etc. there also appear brackish water species such as Melanopsis (Lyrcaea) impressa monregalensis S a c c o, Pirenella plicata moldensis Schaffer, P. plicata quinquenodosa S c h a f f e r, P. plicata trinodosa Schaffer, P. plicata quinquenodosa Schaffer, P. plicata trinodosa Schaffer, Tympanotonos margaritaceus grateloupi d’O r b., which were not encoun- tered in the Chattian and Aquitanian assemblages so far. In the fauna from the Borod basin, according to the salinity degree, there are two types of assemblages : a marine brachy-euhaline one with species belon- ging to the genera Anadaiwand Turritella and a brackish water, meso- pliohaline one with Melanopsis, Pirenella and Tympanotonos (Ș u r a r u &Șuraru, 1973). The Chlamys gigas zone is the only type-biozone that can be used in large correlations; it constantly occurs in the upper half of the nanno- plankton NN1 zone, both in the Middle and East Paratethys and in the Tethys. In the Ehon basin it is described as a subzone between the Fla- bellipecten carryensis and the Chlamys preascabriusculus zones (D e- m a r c q, 1979b). 5. Parvamussium duodeeimlamellatum — Peeten hornensis Zone Locus typicus: Chechiș, Valea Chiriacului, north-west Transyl- vania. Stratum typicum : Chechiș beds. Other important occurrences : Brîglez — at Poieni, Gîlgău-valea Gîl- găuț, Bălan-Valea lui Pătru, Gălpîia-Valea Gălpîiei and Valea Sorților, Eacîș-Valea Jernău, Baica-Valea Băicuța, Sînpetru-Valea Sînpetru, Hida- Valea Dragului, Șoimeni-Pîrîul lui Făncică and Pîrîul Spoielii (all of them in north-west Transylvania); Cornu-Valea lui Sărăcilă, Schiulești- Valea Mare and Valea Crasna (in the subcarpathian foredeep) (see Popa, 1960 ; P o p o v i c i, 1971). Definition. The base of the zone is delimited by the appearanee of the index species Parvamussium duodeeimlamellatum (B r o n n) and Peeten hornensis D e p e r e t & E o m a n, as well as of the species : Peeten fuchsi styriacus H i 1 b e r, Chlamys haueri (Mieht.), Glycy- meris cor dollfusi (C o s s m. & P e y r.), Venus kaltenbachensis H 6 1 z 1, Macoma elliptica ottnangensis (H o r n e s) and Oxystele amedei (B r o n g n). The upper boundary is given by the occurrence of the Peeten beu- danti strictocostata zonal assemblage. Characteristics. The biozone is placed in the Upper Aquitanian (= Middle and Upper Eggenburgian) and in the lowermost part of the Burdigalian and corresponds to the N5 and N6 zones. As far as the nan- noplankton is concerned it is included in the uppermost part of the NN1 zone as well as in the NN2 zone. Institutul Geological României 214 V. MOISESCU, G. POPESCU 10 Remarks. It is a poorly preserved marine euhaline, polytypical assemblage. Most of the specimens are preserved as casts, often out of shape, pelomorphosed. One of the index fossil, namely P. duodecimla- mellatum, by its many occurrences makes the range of the respective bio- zone more complete (Ș u r a r u, 1968). The rocks where the “duodecimlamellatum/hornensis” zone is en- countered are generally clayey deposits, so the facies control is not excluded. This zone was identified in the whole Transylvanian basin wherever the Chechiș beds occur and in the Carpathian foredeep in the Cornu beds and in their stratigraphic equivalents. The zonal assemblage from the Cornu beds does not contain Chlamys gigas, but has in exchange Pecten hornensis eonsidered by Bâldi&Senes (1975) an index fossil for their Pecten hornensis zone. So, the P. duodecimlamellatum — P. hor- nensis zone roughly corresponds to the P. hornensis zone in Hungary and Czechoslovakia. Both in the Transylvanian basin in the Petroșani basin and in other regions in our country, Pecten hornensis does not appear at the level of the Coruș beds or, respectively in the Middle Sălătruc beds. Also, this zone corresponds partially to the Chlamys praescabriusculus zone proposed by Demarcq (1979b) in the Mediterranean 6. Pecten beudanti strictocostata Zone Locus typicus: Hida, dealul Gras, noth-west Transylvania. Stratum typicum : Hida beds. Other important occurrences: Hida-Dealul Corda, Chechiș-Valea Lungă (Șura r u, 1958). Definition. The base of the biozone is delimited by the appearance of the index species Pecten beudanti strictocostata S a c c o, as well as of the species : Pecten aduncus E i c h w a 1 d, P. rollei H 6 r n e s, Flabel- lipecten besseri (A n d r z e j o w s k y), Chlamys malvinae (D u b o i s)- Ostrea duvergieri C o s s m a n n, O. granensis Fontannes, Aporr- hais pes-pelecani alatus (E i c h w a 1 d), N atica millepunctata fulguro- punctata S a c c o, Tubicauda partschi haudmuticus Cossm. & Pey r,. Ocinebrina sublavata grudensis (Hor nes & Au i uger), Euthriofusus burdigalensis acutepernodosus S a e c o, Genota ramosa elisae (H b r n e s & & A u i n g e r). The upper boundary is placed at the occurrence of the zonal as- semblage Neopycnodonte navicularis and Clio falauxi. Characteristics. The biozone is placed in the Burdigalian and cor- responds to the upper part of the N6 zone, N7 zones and the lower part of the N8 zone. The nannoplankton belongs to the NN3 and the lower- most part of the NN4 zones. Remarks. The assemblage is polytypical, marine euhaline with brakish water mio-pliohaline influences, given by the species : Theo- doxus (Vittoclithon) pictus Fbrussac, T. (Calvertia) grateloupianus Fbrussac, Tympanotonos margaritaceus nonndorfensis S a c c o, Pty- Institutul Geologic al României IcR/ 11 CHATTIAN-JBADENIAN BIOCHRONOLOGY IN ROMANIA 215 chopotamides papaveraceum (B a s t.), Potamides schauri H i 1 b e r, Pi- renella plicata plicata (Bruguiere), P. plicata papillata Sandb., P. moravica Horn e s, P. melanopsiformis A u i n g e r, P. peneckei (H i 1 b e r), P. bijuga E i c h w a 1 d, P. trijuga E i c h w a 1 d etc. The Pecten beudanti strictocostata zonal assemblage contains some species and subspecies of molluscs that represent “mutations” of the Chattian and Aquitanian fauna». It, contains many genera, species and subspecies that point out the fact that there is a continuous and intense changing in the Burdigalian fauna. The gradual and continuous deterio- ration of the marine facies during the Burdigalian led to the appearance of facies without organic remains both in Transylvania and in the Car- pathian foredeep. Thus, the Upper. Burdigalian allover the country does not contain organic remains. The foraminifera, the nannoplankton, the macrofauna disappear; their regeneration took place at the base of the Langhian, during the Indo-Mediterranean fauna invasion. We have also assigned all this unfossiliferous interval to the Pecten beudanti stricto- costata zone. This zone is comparable with the Chlamys hermannseni biozone in Hungary and Czechoslovakia. Just like other already mentioned biozones, the index species of Bâldi&Senes did not develop in the Miocene deposits of our country. The important species that characterize it cannot be easily identified, either. Under these circumstances, the P. beudanti strictocostata species proposed as index fossil is the best suited to define this zone in Romania. 7. Neopyenodonte navieularis — Clio falauxi Zone Locus typicus: Copăceni-Pîrîul Racilor, west Transylvania. Stratum typicum: Copăceni-Tureni beds. Other important occurrences : Tureni-Dealul Rugului (L u b e n e s c u et al. 1978); Cluj-Popești area at Dealul Hoia, Dealul Rozelor (north- west Transylvania); Cîlnic, Poiana, Apold, Romoșel (South Transylva- nia) ; Delinești, Lăpugiu, Pane (Banat); Slivuț-Valea Slivuțului, Cinciș, Vîlcelele Bune (Lower Strei basin); Romanii de Sus-Valea Tulburea, Uovăț, Schitu de Jos, Bîlbănești, Breznița (Getic depression); Cîmpina, Slănic, Pietraru-Buzău (Subcarpathian foredeep) etc. (Staneu, Po- pe s c u, 1976). Definition. The base of the biozone is marked by the appearance of the index fossils N eopycnodonte navieularis (Brocchi) and Clio falauxi (K i 111 e), as well as of the planktonic gastropods (Heteropoda and Pteropoda ) : Atlanta oanei S t a n c u, Carinaria andrea S t a n c u, C. rutschi R o b b a, Clio pedemontana (M a y e r), Creseis olteanui Staneu (Stancu, 1974, 1978, 1979). This moment coincides with the beginning of the Indo-Mediterranean faunal invasion characterized by the exuberant development of the plankton. The upper boundary is given by the appearance of the Chlamys latissima nodosiformis zonal assemblage. Institutul Geologic al României \ 16 R 7 216 V. MOISESCU, G. POPESCU 12 Characteristics. The biozone is placed in the Lower Langhian and corresponds to the upper part of the N8 zone and the lower part of the N9 zone (in B 1 o w’s zonation, 1969) or, at the top of the NN4 and lower NN 5 zones (in M a r t i n i’s zonation, 1971). Generally, this biozone corresponds to the lower part of the “Globigerina marls horizon” and to its stratigraphic equivalents. Remarks. The zonal assemblage is made up of specimens belonging to the species Neopycnodonte navimtlaris (Brocchi) and planktonic gastropods that are encountered together with a poor bivalve fauna belonging to the genera Nuculana, Propeamussium, Ostreinella and Relio (St an cu, 1974). It- is a typical marine, euhaline, warm water asem- blage. This stratigraphic interval was also deseribed by L u b e n e s c u et al. (1978) under the name of “Neopycnodonte navicularis biozone”. This zone seems to be correlable with the so called “Karpatian” stage which, due to the nannoplankton content corresponds also to NN4 (upper part) and NN5 (lower part) zones (see : Steininger et al., 1976). The presence of the Chl. latissima nodosiformis in the Karpathian stage (Bâldi&Senes, 1975) is also to be mentioned. 8. Chlamys latissima nodosiformis Zone Locus typicus : Bahna, Bahna basin. Stratum typicum: Curchia limestonc complex (marly-limestones bearing Rhodophytae, an equivalent of the Lagenidae zone). Other important occurrenees : Cinciș, Slivuț, Vîlcelele Bune (Hațeg basin); Popești, ladăra, Benesat, Buciumi (north-west Transylvania); Lăpugiu, Holdea, Coștei, Pane (Banat), in the Șimleu basin (P ancă, 1964 ; N i c o r i c i, 1972, 1978 ; C1 i c h i c i, 1973 ; Caransebeș basin (Florei, 1967 ; S t a n c u & A n d r e e s c u, 1968 ; Lubenescu& SPavnotescu, 1970; Pop, 1972); Bahna basin (M a c o v e i, 1909; M a r i n e s e u & M a r i n e s c u, 1962). Definition. The base of the biozone is delimited by the appearance of the index taxon, Chlamys latissima nodosiformis (De Se r r e s), as well as of the species : Flabellipecten leythajanus (P ar t s h in Ho r- n e s), Chlamys elegans (A n d r z e j o w s k y), Chl. seniensis lomnicki (Hilber), Chl. spinulosa (Goldfuss), Chl. tournali (De Serres), Chl. seissa (F a v r e), Chl. angeloni (M e n n e g h i n i), Chl. angeloni trigonocosta (Hilber), Chl. Ulii (Puch.) The upper boundary is placed at the appearance of the zonal as- semblage Amussium denudatum. Characteristics. The biozone is placed in the Langhian (but not basal) corresponding to the upper part of the N9 zone (= Candorbulina universa — Globorotalia (T.) bykovae Zone). It is also placed at the upper part of the nannoplankton zone NN5. Remarks. With its many occurrenees the index species characte- rises the range of the zonal assemblage in the Middle Langhian of our country. Institutul Geologic al României ksr7 13 CHATTIAN-BADENIAN BIOCHRONOLOGY IN ROMANIA 217 The zonal assemblage has a marine euhaline, polytypical character. Apart from pectinids, there appear many species of molluscs, echinids, briozoans, corals, algae, foraminifera etc. It is worth mentioning that in the Chlamys latissima nodosiformis zone there are some species of Chlamys (e.g. Chlamys scissa and Chl. Ulii) with a much larger geographical area, going beyond not only of the boundary of our country but also of the Paratethys limits. Such species have been met in Mesopotamia, being a new argument for the thesis of the invasion of Indo-Mediterranean origin, identified at the base of the Langhian. 9. Amussium denudatum Zone Locus typieus : Teliucul Superior (quarry), Lower Strei basin. Stratum, typicum : The complex of the siltic strata with interbedded gypsum (at the level of the “evaporitic horizon” and of the deposits im- mediately underlying them). Other important occurrences : Apold, south Transylvania (G h e o r- ghian, 1975); Bozioru-Buzău district, in the Subcarpathian foredeep (S a u 1 e a, 1956). Definition. The base of the biozone is marked by the occurrence of the species Amussium demidatum (R e u s s). as well as of the species Chlamys diaphana (D ub oi s), Chl. scabridus (E i c h w a 1 d), Cleo- dora spina Reuss, Spiratella valvatina (Reuss). The upper boundary is given by the occurrence of the Chlamys wolfi — Chlamys scissa wulkae zonal assemblage. Characteristics. The biozone is placed at the top of the Langhian, corresponding to the so called “Wielician”. It belongs to the N10 zone as well as to the top of the NN5 zone. In the Central Paratethys, at the level of this zone, the Pseudotriplasia biozone (= Wieliczka type assem- blage) has been separated. Remarks. The index species was described by Reuss (1867) from the Wielician stratotype of Wieliczka (Poland). It is encountered there with species of pectinids such as: Chlamys scabridus (Eichw.) and Chl. eichwaldi Reuss, as well as with many other species of molluscs. It is worth mentioning that the Wieliczka zonal assemblage is always accompanied by the solitary coral species Coenocyathus crassus Z e j- n e r5 that aslo appeared in Romania at Teliuc. 10. Chlamys wolfi — Chlamys scissa wulkae Zone Locus typieus : Buituri — Hunedoara district in the Lower Strei basin. Stratum typicum : Sandy clays and clayey sands complex at the upper part of the “Spirialis marls horizon”. 5 Reuss (1867) described this coral as Caryophyllia salinaria. This species was transferied to Coenocyathus crassus Zej sn cr by I, u k o w s k a (1967). Institutul Geological României 218 V. MOISESCU. G. POPESCU 14 Other important occurrences : Minișul de Sus-Zarand basin (N i c o- rici&Sagatovici, 1973; Ni cor ici, 1977; Beiuș basin (Pan că, 1936; Istocescu et al., 1965; Rado, 1971; N i c o- r i c i, 1977); Mehadia basin (11 i e s c u et al., 1968); west Getic basin (Mari nescu et al., 1962); Gîrbova de Sus-Alba district; Seimenii Mari-south Dobrogea; Miorcani-north Moldavia (B i c a I o n e s i in N i c o r i c i, 1977). Definition. The biozone is marked by the appearance of the two index species — Chlamys wolfi (H i 1 b e r) and Chlamys scissa wulkae, Hilber, as well as of the species: Chlamys scissa kneri (Hilber), Chl. scissa richthofeni (Hilber), Chl. Ulii depereti Friedberg, Citi. Ulii biradiata (Quitzow), Chl. neumayri (Hilber) and Chl. varnensis T o u 1 a. The upper boundary is placed at the occurrence of the brackish water mio-brachyhaline faunas of the Lower Volhynian. Characteristics. The biozone is placed in the Nil—N12 zones, or NN6 zone and corresponds to the Kossovian (= Lower Serravalian). Remarks. Besides the above mentioned species of pectinids there are others that have appeared in the underlying zones as well as many species belonging to various genera of molluscs. The species of Pteropods : Spiratella hospes (R o 11 e), S. konken- sis (Zhizh.) and S. nucleatus (Z h i z h.) appear exclusively in this biozone (St an cu, 1974, 1979). We also mention the species Venus konkensis S o k o 1 o v, the most characteristic element of the Konkian stage (East Paratethys). This species appears in Romania at Crivineni and Valea Muncel (Subcarpa- thian foredeep, Buzău district) described here by Pop a-D im ia n (1962) in “Spirialis marls horizon”, in the upper part of the Chlamys wolfi-Chlamys scissa wulkae zone. The species Chl. wolfi and Chl. scissa wulkae characteristic of the biozone with the same name, Avere also encountered in Mesopotamia, in the Euphrat Valley, in the surroundings of the Jebkha Lake (N ic o- r i c i, 1977) pointing out that the connections with the Indo-Pacific area (in Kossovian) Avere preserved Avhile the openings to the Mediter- ranean area Avere closed (Dumitri că et al., 1975). The four zones identified in the Badenian stage (Langhian and Kossovian) correspond in Hungary and Czechoslovakia to the biozones Flabellipecten passinii, FI. besseri and Chlamys elini. We must poin out that Chl. besseri appears in Romania as early as the base of the P. beu- danti strictocostata zone, in the Burdigalian. Then, FI. passinii and Chl. elini are not known in our country so far.- Conclusions. The biozonation based on molluscs (that Avas the object of that paper) correlated Avith the planktonic foraminifera and nannoplank- ton zonations is quite different from the similar biozonations made in the Tethys area (D e m a r c q, 1979b) as Avell as in other regions of the Central Paratethys (see Tables 1, 2). Institutul Geologic al României 15 CHATTIAN-BADEN1IAN BIOCHRONOiLOGY IN ROMANIA 219 So, as compared with that of the Tethys, our biozonation is much more detailed and differs from the former in the upper and basal parts of the investigated chronostratigraphic interval. The only correlable zone between the two areas seems to be the Chlamys gigas zone, identified by D emarcq (1979b) as a subzone at the same stratigraphie level. The great differences appearing between the two biozonations are due to the different paleogeographic evolution of the two great sedimentation areas. The main element in their correlation continues to be the plankton. As compared with B â 1 d i & S e n e s’s zonation (1975) the diffe- rences are also important. So, we mention that in the lower part of the in- vestigated stratigraphie interval the assemblages that prevail in Romania are the brackish water and fresh water faunas, only rarely marine, which do not contain the index species of the other parts of the Central Para- tethys. The most obvious level seems to be the Chlamys gigas zone that in B â 1 d i & S e n e s’s zonation is taken together with the Pecten hor- nensis zone, covering a stratigraphie interval larger than the one of the “gigas” zone in our country. We should point out here that we consider the Schiulești faunas and generativ speaking the faunas of the Cornu beds to be placed at the level of the “duodecimlamellatum/hornensis” zone, above the Chlamys gigas one. The same important differences are noticed at the upper part of the investigated chronostratigraphic interval. Thus, we have correla- ted the biozone with Neopycnodonte navicularis — Clio falauxi with the Chlamys passinii zone, considered as typical for the Karpathian stage. The reason of this correlation lies both in the plankton (with ^sicanus" ) and nannoplancton content (the upper part of the NN4 and the (lower NN5 zone — see Steininger et al., 1976). So the Karpathian stage must be considered as a facies of the Lower Langhian or of the Lower Badenian as it was theoretically defined by Pap p et al. (1968) and Cieha&Senes (1968). The present biozonation made in Romania should be considered a first step liable to many changes that will become necessary during the detailed study of the stratigraphie distribution of the brackish, fresh water and marine faunas. 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