Recognition of cryoturbation for classifying permafrost-affected soils

Cryoturbation is a dominant pedologic process in permafrost-affected soils and is used to delineate Gelisols in soil taxonomy and Cryosols in the Canadian and recently proposed World Reference Base for Soil Resources, and Cryozems in Russian systems of soil classification. In this paper we summarize evidence for cryoturbation that can be used for classifying soils containing permafrost. Based on a literature review and our own observations, cryoturbation in the soil profile is manifested by irregular and broken horizons and textural bands, involutions, organic matter accumulation on the permafrost table, oriented stones, silt caps and accumulations, and deformed soil material associated with movements due to ice- and sand-wedge growth. (C) 1998 Elsevier Science B.V.