cryosequence

A cryosequence refers to a series of soil horizons that have developed under the influence of permafrost or repeated freezing and thawing cycles. These soils are characterized by distinct layers that reflect the impact of cold temperatures on soil formation processes. Key features of a cryosequence often include a surface horizon that experiences seasonal thawing and freezing, known as the active layer. Below this active layer lies the permafrost, a permanently frozen layer of soil, rock, or sediment.

The processes occurring within a cryosequence are significantly different from those in temperate soils. Cryoturbation, the churning and mixing of soil materials due to freeze-thaw cycles, is a dominant process. This can lead to the displacement of soil horizons, creating irregular and contorted patterns. Frost heaving, the upward displacement of soil by ice formation, can also significantly alter soil structure and morphology.

The presence of ice within the soil profile is another defining characteristic. Ice can occur as segregated ice lenses, wedges, or massive ice bodies, all of which influence soil water movement, drainage, and overall soil properties. The type and amount of ice, along with the frequency and intensity of freezing and thawing, dictate the specific morphology and properties of the cryosequence. These soils are found in polar and high-mountain regions where permafrost is present. Understanding cryosequences is crucial for ecological studies, land management, and civil engineering in cold environments.