8. Cryosols of the Circumarctic Region

The circumarctic region contains 11.4 million km², or 83 % of the cryosols worldwide. The climate of the circumarctic varies geographically and is determined by proximity to oceans, elevation, and latitude. Most of the circumarctic contains continuous permafrost. However, discontinuous, sporadic, and isolated permafrost may occur in the Low Arctic. Active-layer depths range from 0.4 to 2.0 m in the Low Arctic, from 0.4 to 1.0 m in the Mid-Arctic, and from 0.25 to 0.9 m in the High Arctic. Common vegetation types in the Arctic are erect shrub land, peaty graminoid tundra, barrens, mineral graminoid tundra, prostrate-shrub tundra, and wetlands. The relief in the circumarctic commonly is flat to undulating with elevations generally below 500 m. Patterned ground is ubiquitous in the Arctic. Cryosols in the circumarctic have been derived from a variety of parent materials, including marine and lacustrine, glacial, windblown, colluvium, and residuum.

Common soil properties of Arctic soils are permafrost within 1–2 m of the surface, cryoturbation, cryodesiccation, and accumulation of segregated ice. Chemical and physical properties vary significantly in response to the action of the soil-forming factors, but the accumulation of organic matter and the development of redoximorphic features are common.

There is a strong latitudinal gradient in soil-forming processes in the Arctic. As one progresses to the north, there is a reduction in redoximorphism (gleization), melanization (organic matter accumulation), podzolization, and textural differentiation and an increase in latitude and an increase in calcification, salinization, and desert pavement formation as the climate becomes more arid.