(from Latin gelare, "to freeze") are soils of very cold climates that contain permafrost within 2
meters of the surface. These soils are limited geographically to
the high-latitude polar regions and localized areas at high mountain
elevations. Because of the extreme environment in which they are
found, Gelisols support only ~0.4% of the world's population - the
lowest percentage of any of the soil orders.
Gelisols are estimated to occupy ~9.1% of the Earth's ice-free land
area and ~8.7% of the US. Although some Gelisols may occur on very
old land surfaces, they show relatively little morphological development.
Low soil temperatures cause soil-forming processes such as decomposition
of organic materials to proceed very slowly. As a result, most Gelisols
store large quantities of organic carbon - only soils of wetland
ecosystems contain more organic matter. Gelisols of the dry valleys of Antarctica are an exception - they occur in a desert environment with no plants and consequently contain very low quantities of organic carbon.
The frozen condition of Gelisol landscapes makes them sensitive
to human activities.
Gelisols are divided into 3 suborders:
Histels, Turbels, and Orthels. Click
here for more information about these suborders. Click
here to view a map of their distribution in the US.