Abstract
Two well-preserved radiolarian assemblages, the older Pantanellium sp.-Spongodiscus quasipersenex and the younger Staurosphaeretta longispina-Amphipyndax stocki, are first recognized and examined in the Shilovka section, south of Ul’yanovsk, East European Platform. The findings are associated with the lower Aptian Volgoceratoides shilovkensis ammonite subzone of the lower part of the Deshayesites volgensis Zone. The enclosing sediments are marked by widespread pyroschists formed under anoxic conditions during accumulation and are correlated with the oceanic anoxic event OAE-1. The radiolarian assemblages are characterized by a strong predominance of spumellarians over nassellarians in number and species diversity and by the occurrence of a lot of taxa unknown from the literature. The peculiarities of the assemblages presumably resulted from the paleoclimate and a shallow epicontinental sea environment.
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Original Russian Text © L.G. Bragina, N.Yu. Bragin, 2015, published in Stratigrafiya. Geologicheskaya Korrelyatsiya, 2015, Vol. 23, No. 2, pp. 81–92.
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Bragina, L.G., Bragin, N.Y. Radiolarians from Aptian deposits of Ul’yanovsk oblast, East European Platform. Stratigr. Geol. Correl. 23, 192–203 (2015). https://doi.org/10.1134/S0869593815020045
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DOI: https://doi.org/10.1134/S0869593815020045