Permafrost Distribution Patterns

The distribution of the differing permafrost types, based on more than 900 observations from northern Victoria Land and through the Transantarctic Mountains, was summarized by Campbell and Claridge (2006). The permafrost table is at greatest

Fig. 2.6 Permafrost types in the Transantarctic Mountains region. The active layer thickness diminishes with increasing coldness and with increasing age and aridity, the permafrost changes from ice bonded to dry permafrost. 1: active layer over ice-bonded permafrost, 2: active layer over buried or massive ice, 3: active layer over dry permafrost over ice-bonded permafrost, 4: active layer over dry permafrost over buried or massive ice, 5: active layer over dry permafrost, 6: saline permafrost depth in the warmer northern regions of Antarctica, and diminishes in depth with increasing latitude and altitude, with some soils possibly being perennially frozen. There is much site variation, however, due to local differences in the heating from radiation owing to topographic shading, aspect, snow cover, surface colour and surface roughness.

Ice-bonded permafrost is most commonly found in coastal regions, on younger-aged surfaces nearest to a glacier and in areas where the precipitation or drainage regime results in moist soils. At higher elevations and greater distances inland, on the older land surfaces and areas of greatest aridity such as parts of the Dry Valleys, dry permafrost, including the intermediate form, predominates. When the transition from one form to another occurs over a short distance, it is commonly related to surface age or moisture availability differences. The ice content of ice-bonded permafrost is usually greatest in coastal regions and least in colder regions. Permafrost is also present in exposed bedrock surfaces, where it may be either ice-bonded or dry.

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