Stratigraphy and the small mammal fauna of the Late Pleistocene sections in the south of the middle reaches of the Volga River

Abstract

Two Pleistocene sections in the middle reaches of the Volga River – Spasskoe and Yagodnoe – have been described in details and analyzed, small mammal remains being recovered and identified. The fauna includes remains of open landscape species: Eolagurus luteus (Eremin and Moloskovsky, 1981), Lagurus lagurus Pallas, 1773, Lasiopodomys (Stenocranius) gregalis (Pallas, 1779) and others. Bone remains of a tundra species – collared lemming Dicrostonyx sp. were found in the Spasskoe section. No forest species are present in the sequence, nor remains of water vole Arvicola. The species richness of the faunas is rather low, which may be related to insufficient amount of material or to a specific climate. Such low species richness is typical of the periglacial faunas of the Pleistocene. The authors of recent article attribute the third Volga terrace to the Late Pleistocene refer usually to the 3rd terrace deposits in the lower reaches of the Volga where the Caspian Upper Khazarian (Hyrcanian) layers are found at the base of the sequence. The rodent molar morphology permits to date fauna to the beginning of the Late Pleistocene (to the early stages of the Valday glaciation) and to reconstruct periglacial steppes widely distributed in the Volga middle reaches at that time.