Permian ammonoids of the Okhotsk Region, Northeast Asia

Abstract

© 2015, Pleiades Publishing, Ltd. Beds with ammonoids are recognized as a result of the study of goniatitids and prolecanitids from the Nyut, Khuren, and Ayan-Yuryakh in the Okhotsk Region. Beds with Neopronorites tenkensis, assigned to the Upper Artinskian Substage, correspond to the upper part of the Echian Horizon of the Verkhoyansk Region. Beds with Paragastrioceras–Baraioceras characterize the middle part of the Kungurian Stage and correlate with the upper sunhorizon of the Tumarian Horizon of the Verkhoyansk Region. Beds with Sverdrupites harkeri correspond to a biostratigraphic subdivision with the same name widely distributed in the Vekhoyansk-Kolyma Region and assigned to the Roadian Stage. The new species Neopronorites tenkensis is described