Ordovician conodont biofacies of the upper La Silla and San Juan formations (middle Tremadocian-lower Dapingian) at Cerro La Silla, Argentine Precordillera
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引用次数: 3
Abstract
Conodonts from the upper La Silla (9.6 m thick) and San Juan formations (264.7 m thick) at the Cerro La Silla section are analyzed for the identification of faunal dynamics, biofacies and sea-level changes. The conodont collection of 11 388 specimens was recovered after digestion of 41 samples of carbonate rocks, totalizing 88.155 kg. Conodont total abundance and generic diversity graphs, as well as cluster analysis, reveal seven biofacies. The Colaptoconus, Tropodus-Reutterodus, Oepikodus-Prioniodus, Juanognathus-Bergstroemognathus, Juanognathus-Oepikodus-Protopanderodus, Juanognathus-Protopanderodus, Juanognathus-Semiacontiodus biofacies are determined. These biofacies represent middle to outer carbonate ramp environments for the San Juan Formation. The associated analysis of biofacies and lithology allow for the recognition of two transgressive events in the San Juan Formation at the Cerro La Silla section, which could be related to transgressive systems tracts (TST) that occurred during the Early and Middle Ordovician (middle Tremadocian-early Dapingian).
期刊介绍:
Comptes Rendus Palevol is a fully electronic and peer-reviewed journal, with a continuous publication stream, devoted to palaeontology, prehistory and evolutionary sciences. It publishes original research results, in French or English, in the following domains: systematic and human palaeontology, prehistory, evolutionary biology and macroevolution, and history of sciences. Thematic issues may also be published under the responsibility of a guest editor. All articles published in Comptes Rendus Palevol are compliant with the different nomenclatural codes. A copyright assignment will be signed by the authors before publication.