permafrost

(redirected from Permafrost soil)
Also found in: Dictionary, Thesaurus, Medical.
Related to Permafrost soil: tundra soil, Discontinuous permafrost

permafrost,

permanently frozen soil, subsoil, or other deposit, characteristic of arctic and some subarctic regions; similar conditions are also found at very high altitudes in mountain ranges. In 1962 measurements in a borehole drilled on Melville Island, Northwest Territories, Canada, showed that the ground was frozen to a depth of at least 1,475 ft (450 m); comparable thicknesses have been found in other far north regions. Tundrastundra
, treeless plains of N North America and N Eurasia, lying principally along the Arctic Circle, on the coasts and islands of the Arctic Ocean, and to the north of the coniferous forest belt.
..... Click the link for more information.
, though underlaid by permafrost, today support centers of population in Alaska, Canada, and Siberia. Permafrost is a very fragile system that may easily be damaged or destroyed by the presence of human-generated heat. A controversy developed in the late 1960s and early 70s over the construction of an oil pipeline from the Alaska North Slope to the southern part of the state. Critics of the project argued that if the pipeline containing hot oil ever came into contact with the permafrost, it would melt the permafrost; the pipeline would then sink and eventually break. The oil spilled during the breakage would result in a major ecological disaster. It was decided to build the pipeline with insulated pipe raised above the permafrost or on gravel beds in order to prevent melting and thus preserve both the pipeline and the ecosystem. In the 21st cent., as the effects of global warming have become particularly strong in the Arctic, permafrost has thawed and destabilized, resulting in dramatically altered landscapes in some areas.

Permafrost

 

a vague term of many meanings applied to the phenomenon of the cooling of rocks on the upper part of the earth’s crust to temperatures of zero and below; the rocks themselves that have hardened as a result of the freezing of the moisture they contained; and the stratum (layer) or zone (region of horizontal spread) of rocks that do not thaw for a long time.

The term “permafrost” was introduced into scientific usage in 1927 by the founder of the school of Soviet geocryologists, M. I. Sumgin, who defined it as ground frost that exists for two to several thousand years. The phrase “ground frost” was not clearly defined in this formulation, and this led to the use of permafrost in various meanings.

As geocryology developed, investigators found themselves increasingly inconvenienced by the word “permafrost,” and as a result it was sharply criticized by P. F. Shevtsov, L. A. Meister, and others in the 1950’s at the V. A. Obruchev Institute of Geocryology of the Academy of Sciences of the USSR. This led to a prolonged discussion of all geocryological terminology. Of the many scientific terms suggested to replace “permafrost,” “perennial frozen rocks” and “perennial cryolithozone” are in widest use.

REFERENCES

Osnovy geokriologii (merzlotovedeniia), parts 1-2. Moscow, 1959.
Materialy po obshchemu merzlotovedeniiu. Moscow, 1959.
Popov, A. I. Merzlotnye iavleniia v zemnoi kore (kriolitologiia). Moscow, 1967.
Dostovalov, B. N., and V. A. Kudriavtsev. Obshchee merzlotovedenie. Moscow, 1967.

A. E. SNOPKOV

permafrost

[′pər·mə‚frȯst]
(geology)
Perennially frozen ground, occurring wherever the temperature remains below 0°C for several years, whether the ground is actually consolidated by ice or not and regardless of the nature of the rock and soil particles of which the earth is composed.

permafrost

Permanently frozen soil, subsoil, or other deposits in arctic or subarctic regions.

permafrost

ground that is permanently frozen, often to great depths, the surface sometimes thawing in the summer
References in periodicals archive ?
Schuster and his colleagues found their measurements were consistent with published data on mercury in non-permafrost and permafrost soils from thousands of other sites worldwide.
Our data showed that the organic carbon content ranged from 1.61% to 3.02% at depths of 13-65 cm, which is comparable with 1.6% in a high Arctic permafrost soil from Spitsbergen reported by Hansen et al.
A total of 15 OTUs of archaea were observed from the Qinghai-Tibetan Plateau permafrost soil, which presented a lower archaeal diversity when compared with other environments.
Guggenberger, "Organic matter composition and potential trace gas production of permafrost soils in the forest tundra in northern Siberia," Geoderma, vol.
The project faces several technical challenges, including the requirement that the gas must be chilled to prevent thawing the numerous underlying ice lenses in the permafrost soils. Chilling the gas, while resolving a likely subsidence problem, creates another.
The main challenge to using HDD was that it had never been used in permafrost soils or in the middle of an Arctic winter, 85 ft below a riverbed.