Paleocryogenic traces of climatic peaks of the Late Pleistocene periglacial hyperzone of the mammoth steppe in soils of archaeological sites

Abstract

Recording and accurate dating of paleo-cryogenic processes traces in modern ecosystems can act as a key for understanding the current state and interpreting the history of landscape development. The stage of the existence of glaciers and the accompanying periglacial zone of the tundra-steppes is the milestone in general history of the Russian large areas. The paleo-cryogenic structures in the modern soil cover are the inheritance of this stage. The recording of said structures at deep levels is possible during archaeological excavations. The stratigraphy of the layers of archaeological sites provides a possibility to link paleo-cryostructures’ traces to certain periods of time and archaeologically date the enclosing context. Preservation of the more complete paleosol record relative to past periods of landscape formation is typical for modern natural zones formed under the affection of limiting factors. These zones include steppe (lack of moisture and excess heat) or tundra (excess of moisture and lack of heat). We recorded the third-order soil polygons preserved on sandy loams of the steppe area in the Orenburg region under the earthfill bunds of the Early Iron Age dwelling. We also recorded the third-order soil polygons under the embankment of a Neolithic-Bronze dwelling on sandy loam soils located in the modern northern taiga zone. In both cases the dimensions of the polygons were about 2-3 meters, and their shape was regular or broken hexagons, resulted from the surface slope or terrain roughness. Moreover, we draw parallels in the history of systems formation, and outlined tasks for further research.