Gelisol

Gelisol
Gelisol
	A Gelisol profile
Used in	USDA soil taxonomy
Profile	OAC
Key process	cryoturbation
Parent material	peat, other
Climate	subarctic, tundra

Gelisols are an order in USDA soil taxonomy. They are soils of very cold climates which are defined as containing permafrost within two meters (6 ft 7 in) of the soil surface. The word "Gelisol" comes from the Latin gelare meaning "to freeze", a reference to the process of cryoturbation that occurs from the alternating thawing and freezing characteristic of Gelisols.

In the World Reference Base for Soil Resources^[1] (WRB), most Gelisols belong to the Cryosols. In soil taxonomy, Gelisols key out before the Histosols. In the WRB, the Histosols key out before the Cryosols. Organic permafrost soils are therefore Gelisols (Histels) in the soil taxonomy and Histosols (Cryic Histosols) in the WRB.

Structurally, Gelisols may have a B horizon and more commonly have an A horizon and/or O horizon resting on the permafrost. Because soil organic matter accumulates in the upper layer, most Gelisols are black or dark brown in soil color, followed by a shallow mineral layer. Despite the influence of glaciation in most areas where Gelisols occur, chemically they are not highly fertile because nutrients, especially calcium and potassium, are very easily leached above the permafrost. The permafrost greatly restricts the engineering use of Gelisols, as large structures (e.g. buildings) subside as the frozen earth thaws when they are put in place.

Gelisols are found chiefly in Siberia, Alaska and Canada. Smaller areas are found in the Andes (mainly near the intersection between Chile, Bolivia and Argentina), Tibet, northern Scandinavia and the ice-free parts of Greenland and Antarctica. Fossil Gelisols are known from as far back as Precambrian ice ages 900 million years ago.

Suborders

In USDA soil taxonomy, Gelisols are subdivided into:

Histels: organic soils similar to histosols except that they have permafrost within two meters (6 ft 7 in) below ground surface. They have 80% or more organic materials from the soil surface to a depth of 50 cm (20 in) or to a glacic layer or densic, lithic, or paralithic contact, whichever is shallowest. These soils occur predominantly in subarctic and low arctic regions of continuous or widespread permafrost. Less than one-third of the active layer (the soil between the ground surface and a permafrost table) or an ice layer which is at least 30 cm (12 in) thick has been cryoturbated.
Turbels: soils that show marked influence of cryoturbation (more than one-third of the depth of the active layer) such as irregular, broken, or distorted horizon boundaries and involutions and areas with patterned ground. They commonly contain tongues of mineral and organic horizons, organic and mineral intrusions, and oriented rock fragments. Organic matter is accumulated on top of the permafrost, and ice or sand wedges are common features. Turbels occur primarily in the zone of continuous permafrost.
Orthels: soils that show little or no cryoturbation (less than one-third of the depth of the active layer). Patterned ground (except for polygons) generally is lacking. Orthels occur primarily within the zone of discontinuous permafrost, and in alpine areas.

References

^ IUSS Working Group WRB (2022). "World Reference Base for Soil Resources, fourth edition" (PDF). International Union of Soil Sciences, Vienna.

Soil Survey Staff: Keys to Soil Taxonomy. 12th edition. Natural Resources Conservation Service. U.S. Department of Agriculture. Washington D.C., US, 2014.
"Gelisols". USDA-NRCS. Archived from the original on 2006-05-09. Retrieved 2006-05-14.
"Gelisols". University of Florida. Archived from the original on September 18, 2004. Retrieved 2006-05-14.
"Gelisols". University of Idaho. Archived from the original on 2006-09-01. Retrieved 2006-05-14.
"Permafrost Soils and Biogeochemistry" (PDF). University of Wisconsin. Archived from the original (PDF) on 2004-03-20. Retrieved 2006-05-14.

External links

profile photos (with classification) WRB homepage
profile photos (with classification) IUSS World of Soils

[1] IUSS Working Group WRB (2022). "World Reference Base for Soil Resources, fourth edition" (PDF). International Union of Soil Sciences, Vienna.

[1]

v t e Soil classification
World Reference Base for Soil Resources (1998–)	Acrisols Alisols Andosols Anthrosols Arenosols Calcisols Cambisols Chernozem Cryosols Durisols Ferralsols Fluvisols Gleysols Gypsisols Histosol Kastanozems Leptosols Lixisols Luvisols Nitisols Phaeozems Planosols Plinthosols Podzols Regosols Retisols Solonchaks Solonetz Stagnosol Technosols Umbrisols Vertisols
USDA soil taxonomy	Alfisols Andisols Aridisols Entisols Gelisols Histosols Inceptisols Mollisols Oxisols Spodosols Ultisols Vertisols
Other systems	FAO soil classification (1974–1998) Unified Soil Classification System AASHTO Soil Classification System Référentiel pédologique (French classification system) Canadian system of soil classification Australian Soil Classification Polish Soil Classification 1938 USDA soil taxonomy List of U.S. state soils List of vineyard soil types
Non-systematic soil types	Sand Silt Clay Loam Topsoil Subsoil Soil crust Claypan Hardpan Gypcrust Caliche Parent material Pedosphere Laimosphere Rhizosphere Bulk soil Alkali soil Bay mud Blue goo Brickearth Brown earth Calcareous grassland Dark earth Dry quicksand Duplex soil Eluvium Expansive clay Fill dirt Fuller's earth Hydrophobic soil Loess Lunar soil Martian soil Mud Muskeg Paleosol Peat Prime farmland Quicksand Serpentine soil Spodic soil Stagnogley Subaqueous soil Takir Terra preta Terra rossa Tropical peat Yedoma
Types of soil

Gelisol

Suborders

See also

References

Further reading

External links