Thermokarst transformation of soil cover on cryolithozone flat territories

Evolution of a biosphere of the Earth and modern climatic conditions have caused a wide spread on a planet of a zone of a long-term frozen ground. On the main evolutionary events on the Earth the glacial ages played a huge role (Fig. 1), covering occurrence of free oxygen in an atmosphere, causing on development of climatic zones, a coming out of plants and animals on continents. In Silurian age as the result of interaction between lithosphere and biosphere arises pedosphere and becomes the powerful factor of evolution on land (Vernadsky, 1940; Kovda, 1973, 1991; John, 1982; Sokolov, 1993). After the formation, by a rule of a feedback, podosphere renders strong influence on the current functioning of biosphere and becomes the specific, difficultly constructed, structural regulator and redistributor of basic streams of substance and the energy, working in system of biosphere - geosphere (Targuljan, 1992). During evolution the soil cover began to represent a self-regulating, a structurally functional subsystem of biosphere of the land, carrying out global functions in regulating atmospheric, hydrospheric, litospheric, biospheric and anthropospheric processes (Dobrovolsky and Nikitin, 1990).