The stratotype region of the Ryazanian stage is located in the Oka River Basin near Ryazan, Central Russia. Since ammonites are very well studied here, we investigated other groups of macrofossils. We report a large n...The stratotype region of the Ryazanian stage is located in the Oka River Basin near Ryazan, Central Russia. Since ammonites are very well studied here, we investigated other groups of macrofossils. We report a large number of bivalve genera: Arctica, Astarte, Buchia, Camptonectes, Chlamys, Ctenostreon, Entolium, Gomomya, Gresslya, Hartwellia, Lima, Meleagrinella, Modiolus, Oxytoma, and Pleuromya. The belemnites are represented by two cylindroteuthidid genera, Acroteuthis and Liobelus. In addition, brachiopods (Rhynchonellidae and Terebratulidae) and unidentifiable gastropod fragments have been revealed. The highest taxonomic diversity of macrofauna is observed in the Surites spasskensis ammonite Zone.展开更多
New data on the litho- and biostratigraphy of the Jurassic/Cretaceous (J/K) boundary interval of the lower reaches of the Lena river, at the Cape Chekurovka and Cape Chucha, are presented. Volgian-Valanginian interval...New data on the litho- and biostratigraphy of the Jurassic/Cretaceous (J/K) boundary interval of the lower reaches of the Lena river, at the Cape Chekurovka and Cape Chucha, are presented. Volgian-Valanginian interval of the Chekurovka section is represented by Buolkalakh and Kigilyakh formations and corresponds to beds with Buchia fisheriana, beds with B. unschensis, beds with B. okensis and B. volgensis, beds with B. volgensis, beds with B. volgensis and B. tolmatschowi and beds with B. keyserlingi. Volgian-Valanginian interval of the Chucha section is represented by Chonoko, Khairgass and Kigilyakh formations and corresponds to beds with B. unschensis, beds with B. volgensis and B. okensis, beds with B. volgensis and B. tolmatschowi and beds with B. keyserlingi.展开更多
文摘The stratotype region of the Ryazanian stage is located in the Oka River Basin near Ryazan, Central Russia. Since ammonites are very well studied here, we investigated other groups of macrofossils. We report a large number of bivalve genera: Arctica, Astarte, Buchia, Camptonectes, Chlamys, Ctenostreon, Entolium, Gomomya, Gresslya, Hartwellia, Lima, Meleagrinella, Modiolus, Oxytoma, and Pleuromya. The belemnites are represented by two cylindroteuthidid genera, Acroteuthis and Liobelus. In addition, brachiopods (Rhynchonellidae and Terebratulidae) and unidentifiable gastropod fragments have been revealed. The highest taxonomic diversity of macrofauna is observed in the Surites spasskensis ammonite Zone.
文摘New data on the litho- and biostratigraphy of the Jurassic/Cretaceous (J/K) boundary interval of the lower reaches of the Lena river, at the Cape Chekurovka and Cape Chucha, are presented. Volgian-Valanginian interval of the Chekurovka section is represented by Buolkalakh and Kigilyakh formations and corresponds to beds with Buchia fisheriana, beds with B. unschensis, beds with B. okensis and B. volgensis, beds with B. volgensis, beds with B. volgensis and B. tolmatschowi and beds with B. keyserlingi. Volgian-Valanginian interval of the Chucha section is represented by Chonoko, Khairgass and Kigilyakh formations and corresponds to beds with B. unschensis, beds with B. volgensis and B. okensis, beds with B. volgensis and B. tolmatschowi and beds with B. keyserlingi.
