The cryogenic structure and texture of seasonally freezing soil in the steppe zone of the Trans-Volga-Urals region

Abstract

The formation of ice lenses and associated frost heave were found in soils the steppe environment with positive mean annual air temperature. The ice lenses due to soil freezing occur in soils with expressed microrelief when they have additional ground moistening. In soils formed on quaternary loam with shallow groundwater the formation of ice was not differentiated across the microrelief; the morphology of the microrelief is similar to thufur. Soils formed on fine-dispersed limestone (chalky polygons) and on the material of ancient weathering crust (frost mounds) do not have clear evidence of subsoil extramoisterning exhibit the differentiated formation of cryotexture according to microrelief. The ice lenses were found in soils of microhights. The formation of cryogenic lenticular and platy structures occur after to the melting of ice lenses in soils. Local frost heave in steppe soils determines the small-scale differentiation of soil processes and the formation of the complex soil cover.