PERMAFROST AND PERIGLACIAL FEATURES | Cryoturbation Structures

摘要: Six types of cryoturbation structures (sedimentary deformations cryogenic origin) can be distinguished and attributed to different mechanisms formation specific environmental conditions. Cryoturbations may result from (1) gravitational loading in thawing soil (‘periglacial loading’), (2) hydrostatic pressure between frozen parts the subsoil (‘cryohydrostatic pressure’), or (3) ice-induced pressures due differential frost penetration (‘cryostatic heave’). The first, most common, process requires a reversed density gradient conditions liquefaction that are possible only during thaw underlying subsoil. other two processes occur freezing. Only large-amplitude periglacial indicate existence perennially ground and, therefore, provide important paleoclimatic proxy indicators. do not require permafrost conditions; they simply deep seasonal repeated freeze–thaw cycles. enhance storage organic carbon influence global cycle.