jeanflop/post_ocr_correction2 huggingface dataset:
Note remise le 29 septembre 1992, acceptée après révision le 17 novembre 1992. RÉFÉRENCES BIBLIOGRAPHIQUES [1] J. POJETA Jr, in T. W. BROADHEAD éd., Mollusks, Notes for a short course, University Tennessee, 1985, p. 102-121. [2] N. J. MORRIS et R. A. FORTEY, J. Paleont., 50, 4, 1976, p. 701-709. [3] J. POJETA Jr et J. GILBERT-TOMLINSON, Dpt. Nat. Res., Bur. Miner. Res., Geol., Geophys., Canberra, Bull., 174, 1977, 64 p. [4] C. BABIN, R. COURTESSOLE, M. MELOU, J. PILLET, D. VIZCAINO et E. L. YOCHELSON, Mém. Soc. Et. scient. Aude, 1982, 63 p. [5] C. BABIN et J. C. GUTIÉRREZ MARCO, Geobios, 18, 5, 1985, p. 609-616. [6] P. G. ACENOLAZA et A. J. TOSELLI, Acta Geol., Lilloana, 14, 1977, p. 55-81. [7] F. G. ACENOLAZA et I. RÁBANO, 5° Congr. Argent. Paleont. Bioestrat., Tucumàn, I, 1990, p. 39-49. [8] M. G. MANGANO et L. A. BUATOIS, 5° Congr. Argent. Paleont. Bioestrat., Tucumàn, I, 1990, p. 51-57. [9] E. SERPAGU, Boll. Soc. Paleont. Ital., 13, 1-2, 1974, p. 19-98. [10] N. E. VACCARI, J. L. BENEDETTO, B. G. WAISFELD et T. M. SANCHEZ, in I. RÁBANO et J. C. GUTIÉRREZ MARCO éd., Libro de Resumenes, Conf. intern. Paleozoico inferior de Ibero-América, Mérida, 1992, p, 148. [11] J. POJETA Jr., Philos. Trans. Roy. Soc. London, 284, 1978, p. 225-246. [12] J. POJETA Jr. et B. RUNNEGAR, In E. R. TRUEMAN et M. R. CLARK éd., The Mollusca 10, Evolution of Mollusca, 1985, p. 295-336. [13] R. D. K. THOMAS, Philos. Trans. Roy. Soc. London, 284, 1978, p. 335-344. [14] C. BARROIS, Ann. Soc. géol. Nord, 19, 1891, p. 134-237. [15] H. Douville, Bull. Soc. géol. France, 4e sér., 12, 7, 1912, p. 419-467. [16] J. POJETA Jr., Geol. Surv. Prof. Pap., 695, 1971, p. 1-46. [17] C. BABIN, Ann. Soc. Géol. Nord, 105, (1985), 1987, p. 253-258. [18] C. BABIN, Mollusques Bivalves et Céphalopodes du Paléozoïque armoricain, Brest, 1966, p. 471. [19] L. LIUEDAHL, Sver. Geol. Undersök., C.N.R. 804, 78, 2, 1984, 82 p. [20] C. BABIN, Confer. intern. Paleozoico inf. de lbero-Amér., Mérida, Resumenes, 1992, p. 43. CONICET, Facultad
de Ibero-América, Mérida, 1992, p, 148. [11] J. POJETA Jr., Philos. Trans. Roy. Soc. London, 284, 1978, p. 225-246. [12] J. POJETA Jr. et B. RUNNEGAR, In E. R. TRUEMAN et M. R. CLARK éd., The Mollusca 10, Evolution of Mollusca, 1985, p. 295-336. [13] R. D. K. THOMAS, Philos. Trans. Roy. Soc. London, 284, 1978, p. 335-344. [14] C. BARROIS, Ann. Soc. géol. Nord, 19, 1891, p. 134-237. [15] H. Douville, Bull. Soc. géol. France, 4e sér., 12, 7, 1912, p. 419-467. [16] J. POJETA Jr., Geol. Surv. Prof. Pap., 695, 1971, p. 1-46. [17] C. BABIN, Ann. Soc. Géol. Nord, 105, (1985), 1987, p. 253-258. [18] C. BABIN, Mollusques Bivalves et Céphalopodes du Paléozoïque armoricain, Brest, 1966, p. 471. [19] L. LIUEDAHL, Sver. Geol. Undersök., C.N.R. 804, 78, 2, 1984, 82 p. [20] C. BABIN, Confer. intern. Paleozoico inf. de lbero-Amér., Mérida, Resumenes, 1992, p. 43. CONICET, Facultad Ciencias Exactas, Físicas y Naturales, Universidad nacional de Córdoba, Vélez Sarsfield 299, 5000 Córdoba, Argentina; Université Claude-Bernard, Lyon-I, Centre des Sciences de la Terre et U.R.A. n° 11, C.N.R.S., 27-43, boulevard du 11-Novembre-1918, 69622 Villeurbanne Cedex. EXPLICATIONS DE LA PLANCHE 1. Localisation du gisement fossilifère. 2-7: Catamarcaia chaschuilensis; 2. moule interne d'une valve droite, CEGH-UNC 10530 (G: x 2,7); 3. moulage latex d'une valve gauche, CEGH-UNC 10531 (G: x 2,7); 4. moulage latex de la charnière de la valve droite CEGH-UNC 10530 (G : x 4); 5. autre vue de la même montrant les petites dents en chevron (G : x 6); 6. moulage latex de la charnière d'une valve droite, CEGH-UNC 10533 (G: x 4); 7. schéma de la charnière d'une valve droite. another aspect of the same showing the small chevron-shaped teeth (M: x 6). 6. latex replica of the hinge of a right valve, CEGH-UNC 10533 (M: x 4). 7. Representation of the hinge of a right valve. PLANCHE PLATE TERESA M. SÁNCHEZ PLANCHE PLATE Paléontologie/Paleontology Évolution paléogéographique de l'Europe au Paléozoïque inférieur : le test des Chitinozoaires Florentin PARIS Résumé — Les Chitinozoaires, éléments importants du paléoplancton de l'Ordovicien inférieur au Dévonien supérieur, sont utilisés pour
interne d'une valve droite, CEGH-UNC 10530 (G: x 2,7); 3. moulage latex d'une valve gauche, CEGH-UNC 10531 (G: x 2,7); 4. moulage latex de la charnière de la valve droite CEGH-UNC 10530 (G : x 4); 5. autre vue de la même montrant les petites dents en chevron (G : x 6); 6. moulage latex de la charnière d'une valve droite, CEGH-UNC 10533 (G: x 4); 7. schéma de la charnière d'une valve droite. another aspect of the same showing the small chevron-shaped teeth (M: x 6). 6. latex replica of the hinge of a right valve, CEGH-UNC 10533 (M: x 4). 7. Representation of the hinge of a right valve. PLANCHE PLATE TERESA M. SÁNCHEZ PLANCHE PLATE Paléontologie/Paleontology Évolution paléogéographique de l'Europe au Paléozoïque inférieur : le test des Chitinozoaires Florentin PARIS Résumé — Les Chitinozoaires, éléments importants du paléoplancton de l'Ordovicien inférieur au Dévonien supérieur, sont utilisés pour éprouver les positions respectives de différentes parties de l'Europe et du nord de l'Afrique durant le Paléozoïque inférieur. Le degré d'éloignement relatif de chacune de ces régions est évalué par un calcul du coefficient de similarité des assemblages de Chitinozoaires entre chaque couple de sites éprouvé. Les résultats corroborent l'hypothèse d'un vaste océan médio-européen (Océan Rheic) s'ouvrant dès l'Ordovicien inférieur et commençant à se refermer dès le Dévonien inférieur. Ils conduisent en revanche à réfuter la notion d'océan sud européen (Océan Prototéthys) au Dévonien inférieur. Palaeogeographic evolution of Europe during the early Palaeozoic: the Chitinozoa test Abstract Chitinozoans are a major component of the Lower Ordovician to Upper Devonian palaeoplankton. They are used for testing the respective position of northern Africa and of different European regions during the Early Palaeozoic. The relative remoteness of each area is evaluated with a coefficient of similarity calculated for the chitinozoan assemblages from each couple of regions tested. The results are in agreement with the existence of a large mid-European ocean (Rheic Ocean) which opened as early as the Lower Ordovician and started to close in the Early Devonian. Chitinozoan data, on the other hand, do not support the concept of a south European
d'un vaste océan médio-européen (Océan Rheic) s'ouvrant dès l'Ordovicien inférieur et commençant à se refermer dès le Dévonien inférieur. Ils conduisent en revanche à réfuter la notion d'océan sud européen (Océan Prototéthys) au Dévonien inférieur. Palaeogeographic evolution of Europe during the early Palaeozoic: the Chitinozoa test Abstract Chitinozoans are a major component of the Lower Ordovician to Upper Devonian palaeoplankton. They are used for testing the respective position of northern Africa and of different European regions during the Early Palaeozoic. The relative remoteness of each area is evaluated with a coefficient of similarity calculated for the chitinozoan assemblages from each couple of regions tested. The results are in agreement with the existence of a large mid-European ocean (Rheic Ocean) which opened as early as the Lower Ordovician and started to close in the Early Devonian. Chitinozoan data, on the other hand, do not support the concept of a south European ocean (Prototethys Ocean) for the Early Devonian. Abridged English Version — Chitinozoans are regarded as an important component of the palaeoplankton from the Lower Ordovician to the Upper Devonian. They are used in this study to test different models of the palaeogeographic evolution of Europe during the Palaeozoic (see references in McKerrow and Scotese, 1990). The geographic distribution of planktonic organisms is mainly controlled by climatic factors which themselves largely depend on latitude. Thus, it is postulated that contemporaneous but highly differing chitinozoan assemblages indicate remote deposition sites in terms of latitude. The sensitivity of this approach is about 10 degrees in latitude, in spite of local perturbations related to major oceanic currents. The aim of the tests is to answer the following questions: (i) Does the palaeontologic record document large differences, at specific level, in chitinozoan assemblages from different European regions? (ii) When did these differences become obvious? (iii) When did they start to fade away ? The tests are based on Clark and Harteberg's coefficient of similarity (Clark and Harteberg, 1983) calculated for different chitinozoan bearing localities of European areas with questionable palaeogeographic affinities (central and southern part of Great Britain, Brabant, Bohemia, Ibero-armorican regions) and of the
in McKerrow and Scotese, 1990). The geographic distribution of planktonic organisms is mainly controlled by climatic factors which themselves largely depend on latitude. Thus, it is postulated that contemporaneous but highly differing chitinozoan assemblages indicate remote deposition sites in terms of latitude. The sensitivity of this approach is about 10 degrees in latitude, in spite of local perturbations related to major oceanic currents. The aim of the tests is to answer the following questions: (i) Does the palaeontologic record document large differences, at specific level, in chitinozoan assemblages from different European regions? (ii) When did these differences become obvious? (iii) When did they start to fade away ? The tests are based on Clark and Harteberg's coefficient of similarity (Clark and Harteberg, 1983) calculated for different chitinozoan bearing localities of European areas with questionable palaeogeographic affinities (central and southern part of Great Britain, Brabant, Bohemia, Ibero-armorican regions) and of the closest major tectonic plates i.e. Baltica (Sweden, Estonia, Podolia, Poland) and the northern part of Gondwana (Algeria, Morocco, Libya) (fig., e). A coefficient of similarity (CS) exceeding 0.75 is usually regarded as indicating close location of the compared sites within a single palaeobiogeographic province (Bergström, 1990). The reliability of the conclusions drawn from these coefficients of similarity depends mainly on three criteria: (i) the constraint of contemporaneity which prevents comparison of chitinozoan assemblages gathering taxa without overlapping total range biozones, (ii) the data used have to be representative of each selected area and the localities with questionable affinities have to be compared with at least two well known palaeogeographic domains, (iii) the homogeneity of the lists of species has to be verified through a detailed synonymy. MIDDLE ARENIG TEST (fig., a). — The data used are from Algeria (Oulebsir, 1992), Morocco (Elaouad-Debbaj, 1984), Sweden (Grahn, 1982), Estonia (Nolvak and Grahn, in press), Bohemia (Paris and Mergl, 1984) and Ibero-armorican domain (Paris, 1981). The very high coefficient of similarity (CS = 0.75) of north African and Ibero-armorican assemblages clearly indicates that both areas were located practically at the same latitude and were part of the same palaeobiogeographic province including in addition
conclusions drawn from these coefficients of similarity depends mainly on three criteria: (i) the constraint of contemporaneity which prevents comparison of chitinozoan assemblages gathering taxa without overlapping total range biozones, (ii) the data used have to be representative of each selected area and the localities with questionable affinities have to be compared with at least two well known palaeogeographic domains, (iii) the homogeneity of the lists of species has to be verified through a detailed synonymy. MIDDLE ARENIG TEST (fig., a). — The data used are from Algeria (Oulebsir, 1992), Morocco (Elaouad-Debbaj, 1984), Sweden (Grahn, 1982), Estonia (Nolvak and Grahn, in press), Bohemia (Paris and Mergl, 1984) and Ibero-armorican domain (Paris, 1981). The very high coefficient of similarity (CS = 0.75) of north African and Ibero-armorican assemblages clearly indicates that both areas were located practically at the same latitude and were part of the same palaeobiogeographic province including in addition the Montagne Noire and Aquitaine (Eremochitina brevis Province). Bohemia was also part of this province (CS from 0.52 to 0.66) whereas Baltoscandinavia was probably fairly remote from northern Gondwana (CS ranging from 0.23 to 0.30). LLANDEILO TEST (fig., b). — The tested data are from Algeria (Oulebsir, 1992), Ibero-armorican regions (Paris, 1981), Aquitaine (Taugourdeau, 1961; Paris, 1987), central Great Britain (Jenkins, 1967), Sweden (Grahn, 1982), Estonia (Nolvak and Grahn, in press). The Llandeilo chitinozoan record for Bohemia is so far incomplete. Nevertheless, its affinities are demonstrated by the occurrence of Linochitina pissotensis, a typical northern Gondwana taxon. The coefficient of similarity for the Saharan platform and SW Europe (CS = 0.84) still indicates very close palaeobiogeographic relationships. The other combinations (CS ranging from 0.26 to 0.39) suggest remote positions of northern Gondwana and southern Europe on one hand and of Baltica and central Great Britain on the other. This result is in favour of an early opening of the Rheic Ocean. However, due to the scarcity of British chitinozoan data the CS related to this area have to be used with caution. The fairly high similarity between the Scandinavian and the Ibero-armorican chitinozoan assemblages (CS = 0.49) is likely related
(Paris, 1981), Aquitaine (Taugourdeau, 1961; Paris, 1987), central Great Britain (Jenkins, 1967), Sweden (Grahn, 1982), Estonia (Nolvak and Grahn, in press). The Llandeilo chitinozoan record for Bohemia is so far incomplete. Nevertheless, its affinities are demonstrated by the occurrence of Linochitina pissotensis, a typical northern Gondwana taxon. The coefficient of similarity for the Saharan platform and SW Europe (CS = 0.84) still indicates very close palaeobiogeographic relationships. The other combinations (CS ranging from 0.26 to 0.39) suggest remote positions of northern Gondwana and southern Europe on one hand and of Baltica and central Great Britain on the other. This result is in favour of an early opening of the Rheic Ocean. However, due to the scarcity of British chitinozoan data the CS related to this area have to be used with caution. The fairly high similarity between the Scandinavian and the Ibero-armorican chitinozoan assemblages (CS = 0.49) is likely related to oceanic currents drifting pelagic forms from Baltica, at medium latitudes, to northern Gondwana, at high latitudes (Henry et al., 1977). MIDDLE LLANDOVERY TEST (fig., c). — The data used are from Saudi Arabia (Paris and Verniers, 1992), Algeria (Taugourdeau, 1962), Libya (Paris, 1988), NW Spain (Cramer, 1967), Bohemia (Dufka, 1992) Brabant (Van Grootel, 1990) and from Estonia (Nestor, 1990). Great similarities (CS = 0.86) are noticed between North Africa and Saudi Arabia chitinozoan assemblages which indicate their location at similar latitudes during the middle Llandovery and their appurtenance to a single palaeobiogeographic province, also including Spain. The low coefficients of similarity with north European assemblages (CS ranging from 0. 19 to 0.31) are consistent with the largest extension of the Rheic Ocean. The higher similarity noticed between Bohemia and Baltica (CS = 0.60) than between Bohemia and northern Gondwana (CS ranging from 0.27 to 0.36) may result from a position closer to the tropic for this area (fig., e) as also suggested by the occurrence of Wenlock limestone in Bohemia. EARLY LOCHKOVIAN TEST (fig., d). — The tested assemblages are from Poland (Wrona, 1980), Podolia (Grahn and Paris, 1992), Bohemia (Paris, 1981, Chlupac et al., 1985), the Armorican massif
1992) Brabant (Van Grootel, 1990) and from Estonia (Nestor, 1990). Great similarities (CS = 0.86) are noticed between North Africa and Saudi Arabia chitinozoan assemblages which indicate their location at similar latitudes during the middle Llandovery and their appurtenance to a single palaeobiogeographic province, also including Spain. The low coefficients of similarity with north European assemblages (CS ranging from 0. 19 to 0.31) are consistent with the largest extension of the Rheic Ocean. The higher similarity noticed between Bohemia and Baltica (CS = 0.60) than between Bohemia and northern Gondwana (CS ranging from 0.27 to 0.36) may result from a position closer to the tropic for this area (fig., e) as also suggested by the occurrence of Wenlock limestone in Bohemia. EARLY LOCHKOVIAN TEST (fig., d). — The tested assemblages are from Poland (Wrona, 1980), Podolia (Grahn and Paris, 1992), Bohemia (Paris, 1981, Chlupac et al., 1985), the Armorican massif (Paris, 1981) and Algeria (Boumendjel, 1987). The Algerian-Armorican couple shows a very high coefficient of similarity (CS = 0.90) which excludes the opening of any large south European ocean during the Early Devonian. The important differences of similarities noticed with north European sites for the previous periods fade away (CS close to 0.50). This is interpreted as the beginning of the closure of the Rheic Ocean. Bohemia is still under lower latitudes than the rest of northern Gondwana. CONCLUSIONS. — Based on chitinozoan evidence the north African shelf and the Ibero-Armorican regions were constantly located at similar latitudes during their northward drift from a polar situation during the Ordovician to a subtropical position in the Early Devonian. In spite of its obvious Gondwana characteristics, Bohemia displayed increasing affinities with Baltica from Llandovery time. This may result from its northern position with regard to the other north Gondwana localities or to the existence of anticlockwise warm currents as documented for middle Ordovician time. The mid-European Rheic Ocean seems to have opened fairly early in the Ordovician. It reached its largest width during the Silurian and was already closing in Lochkovian time. The lack of well documented chitinozoan faunas in Great Britain
close to 0.50). This is interpreted as the beginning of the closure of the Rheic Ocean. Bohemia is still under lower latitudes than the rest of northern Gondwana. CONCLUSIONS. — Based on chitinozoan evidence the north African shelf and the Ibero-Armorican regions were constantly located at similar latitudes during their northward drift from a polar situation during the Ordovician to a subtropical position in the Early Devonian. In spite of its obvious Gondwana characteristics, Bohemia displayed increasing affinities with Baltica from Llandovery time. This may result from its northern position with regard to the other north Gondwana localities or to the existence of anticlockwise warm currents as documented for middle Ordovician time. The mid-European Rheic Ocean seems to have opened fairly early in the Ordovician. It reached its largest width during the Silurian and was already closing in Lochkovian time. The lack of well documented chitinozoan faunas in Great Britain prior to the Upper Ordovician precludes discussion of the importance, or even the existence, of a Tornquist Ocean put forward (Cocks and Fortey, 1982) to separate Avalonia from Baltica up to the late Ordovician. Even if the chitinozoan palaeobiogeographic test is not accurate enough to document the opening of narrow oceans it clearly favours the hypothesis of a large Rheic Ocean and, on the contrary, excludes any large south European ocean during the early Devonian (see references in Van Der Voo, 1988). INTRODUCTION. — Divers schémas d'évolution paléogéographique de l'Europe font intervenir l'ouverture, puis la fermeture de plusieurs espaces océaniques majeurs durant le Paléozoïque. Ces modèles, s'appuyant soit sur des données paléomagnétiques, soit sur les faunes et les sédiments sensibles du point de vue climatique ou encore sur un compromis de ces diverses données (voir références in McKerrow et Scotese, 1990), sont confrontés ici au test des Chitinozoaires, un groupe énigmatique généralement bien représenté dans le paléoplancton de l'Ordovicien inférieur au Dévonien terminal. L'exploitation des formes pélagiques dans le domaine de la palégéographie repose sur un principe simple : la distribution géographique de ces organismes est fortement contrôlée par le climat qui est lui-même largement dépendant des latitudes. Deux assemblages
oceans it clearly favours the hypothesis of a large Rheic Ocean and, on the contrary, excludes any large south European ocean during the early Devonian (see references in Van Der Voo, 1988). INTRODUCTION. — Divers schémas d'évolution paléogéographique de l'Europe font intervenir l'ouverture, puis la fermeture de plusieurs espaces océaniques majeurs durant le Paléozoïque. Ces modèles, s'appuyant soit sur des données paléomagnétiques, soit sur les faunes et les sédiments sensibles du point de vue climatique ou encore sur un compromis de ces diverses données (voir références in McKerrow et Scotese, 1990), sont confrontés ici au test des Chitinozoaires, un groupe énigmatique généralement bien représenté dans le paléoplancton de l'Ordovicien inférieur au Dévonien terminal. L'exploitation des formes pélagiques dans le domaine de la palégéographie repose sur un principe simple : la distribution géographique de ces organismes est fortement contrôlée par le climat qui est lui-même largement dépendant des latitudes. Deux assemblages de Chitinozoaires très dissemblables, mais contemporains, seront donc interprétés ici en terme de fort contraste climatique et, par voie de conséquence, en terme d'éloignement selon les latitudes. D'une façon générale, la sensibilité du test est de l'ordre d'une dizaine de degrés en latitude, malgré les perturbations que certains grands courants océaniques peuvent engendrer sur les isothermes. Le test sera d'autant plus sensible que les climats seront contrastés. MÉTHODE D'ÉTUDE. — Le test proposé doit apporter des éléments de réponses à trois questions : (i) existe-t-il, dans les archives paléontologiques, les preuves de différences sensibles entre les assemblages de Chitinozoaires récoltés dans divers sites d'Europe durant le Paléozoïque anté-Carbonifère? (ii) dans l'affirmative, à quelle période ces différences sont-elles devenues perceptibles? (iii) à quel moment ont-elles commencé à s'estomper, sachant qu'au Carbonifère supérieur l'unité paléogéographique de l'Europe était réalisée? Les assemblages de Chitinozoaires représentatifs de la plaque Baltica d'une part et du nord de la plaque Gondwana d'autre part proviennent respectivement de la marge fennosarmate (exemple : régions balto-scandinaves, Pologne, Podolie) et de la plate-forme bordant le craton africain vers le nord (exemple : Sahara algérien et libyen, sud du Maroc). Les sites européens d'affinité paléogéographique discutée, mais où l'on dispose d'informations