The Santonian Stage in Volsk-Khvalynsk Structural Zone. Paper 1. The Research History and the Composition of Sections

The horizon enriched in glauconite and phosphorite was revealed at the carbonatic outcrops near Volsk in the Coniacian and Campanian stage deposits. The short descriptions of studying sections are presented. The spread of synchronous deposits within Khvalynsky district was traced. The Lower and Upper Santonian and the Campanian age deposits are proved by the presence of the inoceramids, belemnites and echinoides. Its vertical distribution was traced.

New Paleontological and Stratigraphic Data on the Ryazanian Regiostage in the Oka River Sections (Central Russia)

Based on the study of cephalopods and bivalves, the paleontological characteristics of the Ryazanian (lowermost Lower Cretaceous) sections were supplemented in the stratoregion located in the Oka River Basin near Ryazan, Central Russia. The data obtained are important for the analysis of the stratigraphic position in subboreal sections of taxa known in the Arctic, and the subsequent qualitative development of the zonal level of scales for belemnites and buchias of the Jurassic-Cretaceous boundary interval of the Russian Plate.

Upper Cretaceous Deposits and Biostratigraphy of the «Novospasskoe» Section (South-West of the Ulyanovsk Region)

The section of campanian deposits of the south-west of the Ulyanovsk region characterized by a strata of “knotty” chalk is described. It was found relatively numerous faunal complex presented mostly by belemnites, bivalves and echinoids. The diversity of epibiontic organisms is described. The study of fauna has helped clarify stratigraphic position of the section within the scope of valid regional scheme.

Integrated Bio and Magnetostratigraphic Study of the ≪Ozerki≫ Sections (Upper Cretaceous, Right Bank of the Volga in the Saratov Region). Paper 2. Oryctocoenosis Characteristics and Biostratigraphy

In the ≪Ozerki≫ sections, in the terrigenous and carbonate rocks, a faunal complex has been determined – unusually diversified and relatively abundant for the right-bank part of the Saratov Region. Examination of the specified groups of fossil invertebrates has allowed to propose variants for biostratigraphic division and correlation of the sections under consideration. The carbonate rocks are supposed to belong to the Turonian-Coniacian and the underlying terrigenouscarbonate rocks are regarded as the Lower Turonian ones.