Cryogenic Soil Processes - Cryopedology - page 58

Fig. 5.8 Thermo-hydro-
mechanical interaction
mechanism in freezing soils
(Thomas et al. 2009 )

5.4 Modeling Cryogenic Soil Processes

Thomas et al. ( 2009 ) used a numerical approach to model cryogenic processes in
permafrost-affected soils (Fig. 5.8 ). The model considered soil freezing and ice seg-
regation. During two-sided freezing, ice segregation took place in a closed system,
with ice lenses accumulating at the base of the active layer and near the ground
surface, leaving an intervening ice-poor zone. Numerical modeling was able to rep-
resent the development of both the thermal fi eld and ice segregation observed in the
physical models. The signifi cance of this contrasting ground ice distribution is con-
sidered in the context of thaw-related slow mass movement processes
(gelifl uction).

5.5 Summary

Although soil-forming processes, such as humifi cation, paludifi cation, podzoliza-
tion, 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 defi nitions
of soil-forming processes. Cryogenic processes include frost heaving, cryoturba-
tion, 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