THE MIDDLE-LATE PLEISTOCENE STRATIGRAPHY AND PALEOGEOGRAPHY IN RYBINSK-YAROSLAVL REGION NEAR THE VOLGA RIVER

Abstract

New results of a comprehensive investigation are used to substantiate the stratigraphic position of marker beds in the Rybinsk reference section, and to analyze periodic changes in paleogeography during the middle-late Pleistocene. Different glacial and interglacial deposits widespread in reference sections of the Yaroslavl region adjacent to the Volga River are discriminated on the basis of mineralogical, petrographical, and palynological criteria. Correlative lithologic features of the Dnieper, Moscow, and Kalinin moraines, which differ in occurrence mode, inner structure, and composition, are depicted to solve problems concerning these controversially interpreted deposits. Their stratigraphic relations to the Mikulino and early Valdai limnic deposits are outlined. Relevant data of spore-pollen analysis are used to reconstruct the landscapes and climatic conditions that existed during the entire stratigraphic interval of the Mikulino interglaciation. The documented traces of two early Valdai interstades are preceding the latest glaciation in the region, and suggest the late Pleistocene (Kalinin) age of the upper moraine.