ABSTRACT

In all areas subject to freezing and thawing, the rocks exposed at the surface will be subjected to additional stresses by the extreme temperature changes (diurnal and seasonal) that occur in these places. Moisture in the rock greatly increases the stresses by phase changes and by chemical reactions between the minerals and the dissolved gases in the water, e.g., carbon dioxide. Dissolved salts in the soil water can crystallize out and exert additional pressures inside crystal grains due to the forces of crystallization. Ice lenses may develop in the sediment or rock, and can break the material apart. As a result, there is enhanced weathering and production of coarse detritus (sometimes referred to as cryogenic weathering) , the products of which can then commence moving down the slope. They may also accumulate on mountain tops. In Russia, these are collectively referred to as kurums.