Soil or rock at temperatures of 0C or lower. The terms 'cryotic' and 'non-cryotic' were introduced to solve a major semantic problem identified by Brown and Kupsch (1974), namely the lack of specific
separate terms to designate 'above 0C' and 'below 0C' as opposed to 'unfrozen' (not containing Ice) and 'frozen' (containing Ice). Cryotic and noncryotic refer solely to the temperature of the material described, independent of its water or Ice Content. Perennially Cryotic Ground refers to ground that remains at or below 0C continuously for two or more years and is therefore synonymous with Permafrost.
Cryoturbation (frost churning) refers to the mixing of materials from various horizons of the soil right down to the parent rock due to freezing and thawing. Cryoturbation occurs to varying degrees in
most Gelisols (permafrost soils). The cause of crytoturbation lies in the way in which the repeated freezing of the soil during autumn causes the formation of ice wedges at the most easily erodible parts of the parent rock. If the parent rock is hard, this can cause quite deep erosion of the rock over many years. As this process continues, during the summer when an active layer forms in the soil this eroded material can easily move both from the soil surface downward and from the permafrost table upward. As this process occurs, the upper soil material gradually dries out (because the soil moisture moves from the warm surface layer to the colder layer at the phen of the permafrost) so that it forms a granular structure with many very distinctive crystalline shapes (such as ice lenses). Separation of coarse from fine soil materials produces distinctive patterned ground with different types of soil.
(1) (singular) a collective term used to describe all soil movements due to frost action (2) (plural) irregular structures formed in earth materials by deep frost penetration and frost action processe
s, and characterized by folded, broken and dislocated beds and lenses of unconsolidated deposits, included organic horizons and even bedrock.
1. (Singular) A collective term used to describe all soil movements due to frost action; 2. (Plural) Irregular structures formed in earth materials by deep frost penetration and frost action processes
, and characterized by folded, broken and dislocated beds and lenses of unconsolidated deposits, included organic horizons and even bedrock
(Singular) A collective term used to describe all soil movements due to Frost Action irrespective of the existence of Permafrost. (Plural) Irregular structures formed in earth materials by deep Frost
Penetration and Frost Action processes, and characterized by folded, broken and dislocated beds and lenses of unconsolidated deposits, included organic horizons and even bedrock. Note: Cryoturbation encompasses Frost Heave, thaw settlement and all differential movements, including expansion and contraction due to temperature changes and the growth and disappearance of Ground Ice bodies, whether perennial or seasonal. Low temperatures alone are not enough to produce Cryoturbation; the water-ice phase change is necessary. Cryoturbation is an important process in the development of Patterned Ground.