Proceedings Chapter
Reference
Variations in coral faunas across the Pliensbachian- Toarcian crisis: a diachronous event?
VASSEUR, Raphaël, et al.
VASSEUR, Raphaël, et al . Variations in coral faunas across the Pliensbachian- Toarcian crisis:
a diachronous event? In: The Fossil Week, 5th International Palaeontological Congress . Paris : 2018. p. 561
Available at:
http://archive-ouverte.unige.ch/unige:109149
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5th International Paleontological Congress – Paris, 9th-13th July 2018
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Variations in coral faunas across the Pliensbachian- Toarcian crisis: a diachronous event?
Raphaël Vasseur*
1, Simon Boivin†
2, Bernard Lathuilière
1, Iuliana Lazar
3, Christophe Durlet
4, Rowan Martindale
5, Stéphane Bodin
6, Khalid El Hmidi
71 GEORESSOURCES (G2R) – INSU, CNRS : UMR7359, Université de Lorraine – Faculté des Sciences et Technologies
”Entrée 3B” rue Jacques Callot BP 70239 54506 Vandoeuvre-lès-Nancy Cedex, France
2 University of Geneva, Department of Earth Sciences – Rue des Maraîchers 13, 1205 Geneva,Switzerland 3 University of Bucharest Faculty of Geology and Geophysics Department of Geology and Paleontology, 1, N. Balcescu
Ave., RO – 010041, Bucharest., Romania
4 Université de Bourgogne Franche-Comté, UMR CNRS 6282 Biogéosciences– 6 Bvd Gabriel 21000 DIJON, France 5 University of Texas at Austin, Department of Geological Sciences – University of Texas at Austin 1
University Station C1100 Austin, TX 78712, United States
6 Department of Geoscience, Aarhus University – Høegh-Guldbergs Gade 2 8000 Aarhus C, Denmark
7 Département de l’Energie et des Mines Direction de la Géologie – Rue Abou Marouane Essaadi BP 6208, Haut Agdal, Rabat, Morocco
The boundary between the Pliensbachian and Toarcian stages of Lower Jurassic (Upper Lias) is an important interval for the understanding of worldwide ecological turnovers. This interval records evidence of important biological extinction events concerning different taxonomic groups as well as markers of major paleoenvironmental modifications. At the Pliensbachian/Toarcian boundary, groups such as ammonites, brachiopods, and bivalves suffered huge faunal turnovers at different taxonomic scales; which have been temporally linked with the Karoo-Ferrar large igneous province in Southern Pangea. In addition, large-scale negative excursions of the δ13C record and significant variations of 87Sr/86Sr ratio at both the Pliensbachian/Toarcian boundary and within the Toarcian Oceanic Anoxic Event (T-OAE) indicate that there are global perturbations to the carbon cycle and other geochemical cycles in this interval. At the T-OAE, these perturbations correspond to significant organic matter-rich strata (black shales) in Europe, North America, and South America. Associated to these events, global reef collapses have been documented;
there is a 99% loss of reef carbonate production recorded worldwide. Bibliographic studies of Lathuilière and Marchal (2009) about populations of corals (cnidarians) fossils suggest a significant extinction in this group for the same period. C are particularly sensitive indicators of major ecological perturbations, as evidenced by their significant turnovers during the ”Big 5” biological crisis. This presentation reports on a work in progress, which aims to characterize and quantify the faunal turnovers suffered by corals across the Pliensbachian/Toarcian boundary as well as across the T-OAE. The distinction of the ecological turnover and impacts of each of these two events will open new perspectives in the interpretation of the data and results in terms of paleoecology and taxonomic turnovers. We are addressing this question in the southern Atlas of Morocco, where Pliensbachian and Toarcian deposits are exceptionally expanded in comparison to other localities worldwide.
* Speaker
† Corresponding author: simon.boivin@unige.ch
