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Fig. 3.1 Idealized sketch of an ice-wedge polygon showing types of cryoturbation features,
including ( 1 ) irregular horizons, ( 2 ) deformation of textural bands, ( 3 ) broken horizons, ( 4 ) involu-
tions and diapirs, ( 5 ) the accumulation of fi brous or partially decomposed organic matter on top of
the permafrost table, ( 6 ) oriented stones, ( 7 ) silt caps from vertical sorting, and ( 8 ) upwarping of
sediments adjacent to the ice wedge (Bockheim and Tarnocai 1998 )
Table 3.2 compares soil horizon nomenclature for the US, Russian, Canadian,
and WRB systems. There are several symbols and suffi xes for soil horizon nomen-
clature that apply primarily to cryosols. The symbol “Wf” is used for describing ice
wedges; the symbol “I” is used in the WRB. The suffi xes “f” and “ff” are used for
ice-cemented and dry-frozen permafrost, respectively. The suffi x “jj” is used for
horizons showing cryoturbation. As will be seen in Chap. 6 , the use of these sym-
bols is very important for classifying soils from soil descriptions.
The most common macroscopic soil features are due to cryoturbation and include
irregular or broken horizons and incorporation of organic matter in lower horizons,
especially along the top of the permafrost. Oriented stones and displacement of soil
materials are common in cryosols. Freezing and thawing produce granular and platy
structures in surface horizons and blocky, prismatic or massive structures in subsur-
face horizons. The massive structure is due to cryostatic pressure and desiccation
that develop when the two freezing fronts, one from the surface and the other from
the permafrost, merge during freeze back in the autumn. The perennially frozen
layer commonly contains ground ice in the form of segregated ice crystals, vein ice,
ice lenses and wedges, and thick ground ice.
The granular, platy, or blocky structures of the surface mineral horizons are also
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