5. Cryogenic Soil Processes

Although soil-forming processes, such as humification, paludification, podzolization, and gleization operate in cryosols, the dominant processes are of cryogenic origin. Cryogenic processes involve inputs, outputs, transfers, and transformations of energy, water, and soil material and, therefore, according to classical definitions of soil-forming processes. Cryogenic processes include frost heaving, cryoturbation, dilatancy, cryodesiccation, and ice segregation. These processes are evidenced at the landscape scale in the form of patterned ground, at a pedon scale in the form of cryoturbation, dilatancy, ped forms, and cryodesiccation features, and at the microscopic scale from compaction, displacement of plasma or skeletal grains, and pore formation. Cryopedologic processes are utilized in the definition of cryosols or gelisols and at the second highest level in distinguishing whether or not cryoturbation is observed in mineral soils. Numerical models of cryopedogenesis have focused on specific processes such as heaving, formation of segregation, and cryoturbation.