Brachiopods as indicators of the Upper Devonian Frasnian sedimentation in the Timan-Pechora oil and gas province
Year: 2024
Type: article
Abstract: The paper describes faunal complexes formed in the north of the European part of Russia under different facies conditions during the Frasnian stage of the Upper Devonian period.The main inhabitants of the Frasnian sea basin were cephalopods -ammonoids and bactritoids, characterized by a rich species diversity of brachiopods, ostracods, bivalves, echinoderms, conodonts, coniconchians and radiolarians.These complexes are somewhat similar to the Frasnian complexes of the Russian Platform and the Western slope of the Ural Mountains.A particularly important role in the division of the Frasnian sections played brachiopods -inhabitants of the 30-200 m depth intervals of the warm shallow-water basins with normal salinity.Characterized by characteristic bi-valve, bilaterally symmetrical shells with different relief, these brachiopods are the most important indicator of the physicochemical conditions of sedimentation.To date, more than sixty brachiopod species with different shapes, sizes and shell surface structures have been detected and described in the Upper Devonian Frasnian stagsse of the Timan-Pechora oil and gas province.Each substage, horizon and formation of the Frasnian stage is characterized by its own set of brachiopod species distinguished for their specific morphological features.It brings to a conclusion that the studied rocks had been formed under different facies conditions during four major sedimentation cycles -the Timan (Timan formation), Khvorostan (Ustyarega formation), Semiluk (Domanik and Vetlasyan formations) and Don (Sirachoy and Ukhta formations).
Authors: L.P. Bakulina, Y.G. Dovjikova
Language: English
Subfield: Paleontology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4403545269