Basic Features of Late Pleistocene Soil Formation in the East European Plain and Their Paleogeographic Interpretation

Large-scale climate fluctuations reflected in the alternation of glacial and interglacial epochs have resulted in structural changes in the landscape shell. Differences in heat and moisture supply have accounted for specific features of soil-forming processes, zonality structure, and the ratio of soil formation and sedimentation processes. The sequence of types of soil formation epochs is most completely reflected in the structure of loess-soil cryogenic formations, where specific features of soil formation and sedimentation during no less than seven natural climatic macrocycles (over the past 800 ka, the Brunhes paleomagnetic epoch) have been revealed and analyzed. Within macrocycles, three main types of soil formation epochs have been distinguished: interglacial, interstadial, and pleniglacial (interphasial). Interglacial soil formation evolved from subtropical in the Eopleitocene and Early Pleistocene to subboreal and boreal in the Middle and Late Pleistocene. Interstadial dark-colored soils developed during early interstadial warmings at the beginning of glacial epochs and formed complexes with interglacial soils. Pleniglacial soil formation was characteristic of the coldest phase of the Valdai glaciation, when sedimentation and physical weathering absolutely prevailed over soil formation, leading to the development of specific synlithogenic soils. In the periods of climate softening, interstadial soils of cryo-gley genesis were formed.