Lower Callovian of Kanev Dislocations, Cherkasy Oblast, Ukraine: Ammonites and Stratigraphy

The Jurassic rocks of the area of Kanev glacial dislocations (Central Ukraine) with the Bathonian coastal marine (lagoon) and the Lower Callovian normal marine sediments have been studied, the upper part of which was unknown to the predecessors. The zonal and infrazonal scale of the Lower Callovian of Kanev dislocations are elaborated by ammonites and include four zones, five subzones, and 14 biohorizons: Elatmae Zone (the upper part: P. elatmae and P. vasily biohorizons); Subpatruus Zone (the uppermost part: Ch. saratovensis (G. toricelli) Biohorizon); Koenigi Zone with the Gowerianum (G. metorchum and G. gowerianum biohorizons), Curtilobum (G. indigestum, G. curtilobum, and G. crucifer biohorizons), and Galilaeii (G. galilaeii, s.l. Biohorizon) subzones; Calloviense Zone with the Calloviense (S. khvalynicum and S. kiselevi biohorizons) and Enodatum (C. enodatum planicerclus, C. e. enodatum, and C. e. aeeta biohorizons) subzones. This scale is compared with those of European Russia and Western Europe. It is found that the base of the Proplanulites koenigi Zone, which was distinguished by Karitzky (1887) in the sections of the north Kanev dislocations, biostratigraphically corresponds to the base of the eponymous Zone, which was distinguished by Buckman (1913) in North Yorkshire and used in a standard scale of Europe. The ammonites of the families Cardioceratidae, Kosmoceratidae, Perisphinctidae, and Macrocephalitidae common in the Early Callovian in the East European marine basin are revised and their evolution and biogeography are analyzed. It is shown that, at the beginning of the Callovian, this vast young epicontinental basin was a “pot” of neoendemic evolution of various groups of ammonites, which migrated from Arctic, West European, and West Tethyan biochorems. The western (Dnieper–Donets) marine area of the basin, which also includes the area of Kanev dislocations, was a main way for migration of marine organisms between the West and East European paleobiogeographic provinces. New species are described: Paracadoceras vasily Gulyaev, sp. nov., Sigaloceras fundator Gulyaev, sp. nov., and S. kiselevi Gulyaev, sp. nov.