Radiolarians of the upper Cenomanian and lower Turonian from deposits of the Ananuri Formation, the western Caucasus (Lazarevskoe area) |
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| Authors: | L G Bragina Yu V Agarkov N Yu Bragin |
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| Institution: | (1) Geological Institute, Russian Academy of Sciences, Moscow, Russia;(2) Rostov State University, Rostov-on-Don, Russia |
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| Abstract: | Diverse radiolarians (over 70 species) are detected in cherty rocks above the bituminous shale horizon, the marker of anoxic event OAE-2 recorded across the Cenomanian-Turonian boundary in the upper part of the Ananuri Formation of flyschoid deposits, the Lazarevskoe area of the western Caucasus. The radiolarian assemblages studied are comparable in composition with radiolarians from concurrent Cenomanian-Turonian boundary strata in other Mediterranean regions (e.g., in the Crimea and Turkey). The lower radiolarian assemblage includes index species Dactyliosphaera silviae of synonymous Cenomanian zone. Alievium superbum present in the upper assemblage is index species of the relevant Turonian zone. Within the studied flyschoid sequence, sediments indicative of the above event (bituminous shales and cherts) are confined to upper elements of flysch rhythms. |
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| Keywords: | western Caucasus Cenomanian Turonian radiolarians anoxic events flysch |
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