DETAILED LATE PLEISTOCENE PEDOLITHOSTRATIGRAPHY OF PERIGLACIAL AREAS OF THE EAST EUROPEAN PLAIN BASED ON THE STUDY OF PALEODEPRESSIONS

In periglacial zones, the Late Pleistocene climatic cycles were reflected in stratigraphic sequences that consist of paleosols divided by geological deposits. The pedolithogenic sequences were preserved in paleo-gullies incised shortly prior to the glaciation. Here we present the sequence of Late Pleistocene paleosols described in various paleodepressions within the Eastern European Plain.

The interglacial (MIS 5e) Ryshkov paleosol (rank 5) is bedded at the base of the Late Pleistocene depositional sequences. The paleosol is complex: 3 to 4 phases of soil formation were alternated by short episodes of sedimentation. The soils of the first phase are Chernozems (Mollisols) typical for grasslands. During the second and third phase, Luvisols typical for the forest-steppe transition zone were formed. The final stage was marked by a catastrophic fire.

Two paleosols, Kukuev, rank 2 (MIS 5c), and Streletsk, rank 3 (MIS 5a) were formed in the Early Valdai in relatively mild climatic conditions. Each paleosol underwent two phases of pedogenenis: the initial stage was Chernozemic and the final stage was Luvisol. The paleosols were divided by the episode of sedimentation during the cooling phase – Mlodat stadial (MIS 5b).

Beginning of pleniglacial (MIS 4) is reflected in the accumulation of colluvial-solifluction deposits and formation of massive cryogenic structures.

Two interstadial paleosols, Aleksandrov (rank 2) and Bryansk (rank 3) were formed during the Middle Valdai (MIS 3). The paleosols are divided by colluvial-solifluction deposits (Tuskar stadial). Lenses of a gley loam were formed within the Tuskar deposits, indicating a warmer climatic episode.

The Bryansk paleosol was deformed by cryogenic processes in the beginning of the full glacial (MIS 2) and overlain by loess deposits.

The above-described paleosols correspond to the following interstadials: Ryshkov=Mikulino=Eemian interglacial, Kukuev=Brorup+Amersfort=St. Germain 1 interstadial (115-105 kyrs BP), Streletzk=Odderade=St. Germain 2 interstadial (70-80 kyrs BP), Aleksandrov = Oerel interstadial (55-50 kyrs BP), Kostenki lower soil (14-II) =Moersfood=Poperinge interstadial, Tuskar gley loam=Hengelo interstadial (38-40 BP), Bryansk=Denekamp interstadial (30-25 kyrs BP).

This research was supported by RFBR grant 11-05-01046.