Ammonites, Microfauna, and Palynomorphs from the Lower Part of the Upper Bajocian Parkinsoni Zone of the Basin of the Bolshoi Zelenchuk River, Northern Caucasus

Abstract

This paper contains the results of a comprehensive study of the standard Rarecostites subarietis Subzone of the upper Bajocian Parkinsonia parkinsoni Zone in sections on the Kyafar River (a tributary of the Bolshoi Zelenchuk River, Karachay-Cherkessia, Russia). The subzone is represented by shales with marl interbeds and sideritic concretions of the upper member of the Djangura Formation. The taxonomic composition and distribution of ammonites, foraminifers, ostracodes, dinoflagellate cysts, and miospores are established. The characteristic assemblages recognized of microfauna and palynomorphs enabled the recognition of foraminiferal and dinocyst biostratigraphic units for this Middle Jurassic interval. The index fossils are illustrated.