The Impact of Paleocryogenesis on the Formation of Gray Forest Soils in Central Russia

摘要

The paleogeographic development of the natural process in the Late Pleistocene on the East European Plain had a rhythmic pattern with repeated alternation of cold and warm climatic eras. Continental glaciations arising on the East European Plain, in particular, the Late Valdai (Weichselian) glaciation, were reflected in changes in topography formation. Regional paleoenvironmental conditions of the formation of modern soil cover in the area of gray forest soils in central Russia are discussed. The impact of paleocryogenesis on the features of the Holocene soils is considered by the example of Vladimir and Moscow oblasts. In Vladimir oblast, soils were studied in Suzdal district on the territory of the Kibol-5 archaeological site of the early Middle Ages. In Moscow oblast, studied were conducted at the Pushchino key site. The differentiation of soil profiles related to the specificity of parent materials formed under the impact of the Late Weichselian paleocryogenesis with the development of cryogenic microtopography was demonstrated. It was also found that the surface microtopography is predetermined by the buried paleocryogenic polygonal network of elevated blocks (microhighs) and interblock depressions (microlows). The paleocryogenic genesis of this microtopography caused by cryogenic deformation of large wedge-shaped features was confirmed. Large cryogenic wedge-shaped soil features in the study area formed about 22-14 ka ago, which is confirmed by radiocarbon data. The dependence of the Holocene loamy soils in central Russia on the characteristics of parent materials is manifested at the levels of soil profiles, soil horizons, and particular soil properties. It is argued that the presence of Late Pleistocene paleocryogenic features greatly affects the formation of the profiles of Holocene soils and enhances the action of the anthropogenic factor on soil development. As an environmental factor, Late Weichsel paleocryogenesis differentiates soils at the high taxonomic level contributing to the formation of complex soil cover patterns.