ИСТИНА

Russian Plain was influenced by at least six Pleistocene ice sheets, among them two ice-sheets have determined the pattern of surface glacial and periglacial sediments: more extensive Moscow (Late Saalian) and less extensive Valday (Weischelian) ice sheets. So the pattern of surface glacial and periglacial sediments follow three conspicuous belts: 1. An area south of Moscow limits is characterized by extensive loess mantles of East-European loess belt. Polygenetic features in Faeozems and Chernozems are determined by loess stratification, marked by paleocryogenesis, paleohydromorphism and relic soil features. 2. An area within Moscow glacial limits is characterized by a diverse set of surface sediments as a result of complex glacio-dynamic structure of the ice-sheet and high dissection of relief. On the highest positions (200 -250 m a.s.l.), thick cover (3 to 5 m) of mantle loams (northern variety of loess) overlay glacial till. In the intermediate positions (170-200 m a.s.l.) a thin veneer of fluvioglacial sediments over glacial till (30-70 cm) form bipartite sediments. Cover layers include separate patches or admixture of aeolian silt simultaneous to the deposition of fluvioglacial sands. Sandur sediments cover the surfaces below 170 m a.s.l. 3. Within Valdai glacial limits high flooding prevented extensive loess accumulation. Loess sediments are quite rare and often merge with lacustrine loams. Soils inherited specific layering of sediments (laminated clays, fluvioglacial sands and glacial till with veneer of fluvial sand; on higher levels glacial till with thin veneer of cover sand. Loess sediments within the profiles of surface soils and especially small aeolian additions need to be further investigated in relation to glacial history to reconstruct paleoenvironments during the final stages of deposition of surface sediments.