Characteristics of Cryogenic Weathering in the Permafrost Zone of the European Ussr^*

* An earlier version of this paper was published as V. N. Konishchev (1978), Vestnik Moskovskogo Universiteta, Geografiya, 5: 11-18.

Abstract

Changes in the distribution of rock forming minerals, such as quartz, feldspars, amphibolines, and pyroxenes, with respect to grain size, are examined within the context of loessic sediments of the northern European USSR. Contrary to trends in temperate or warm climates, quartz is characterized by a high degree of instability under cryogenic conditions and is the cause of the dominant silt fraction (0.05 to 0.01 mm). The yield of heavy minerals is also unusual in that the 0.05 to 0.01-mm fraction is lower than that in the 0.05 to 0.1-mm fraction. An attempt is made to classify soils according to their grain size and mineralogical composition, and to distinguish those formed predominantly by cryogenic processes.