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. Tundras tundra , 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 man-made 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.

permafrost

Perennially frozen earth, with a temperature below 32 °F (0 °C) continuously for two years or more. Permafrost is estimated to underlie 20% of the Earth's land surface and reaches depths of 5,000 ft (1,500 m) in northern Siberia. It occurs in 85% of Alaska, more than half of Russia and Canada, and probably all of Antarctica. Permafrost has a significant effect on plant and animal life, and it presents special problems in engineering projects. All land use in permafrost environments must take into account the terrain's special sensitivity; if the delicate natural balance is not maintained, extensive degradation and ecological damage may result.

permafrost

ground that is permanently frozen, often to great depths, the surface sometimes thawing in the summer

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

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

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No references found			The SLF scientist points out that "extremely hot periods"--for instance the summer of 2003 and July 2006--resulted in deepening the active layer of rock walls with increased creep rates and rock fall in Alpine permafrost. UNESCO label aids glacial protection by Shepard, Lyn / Swiss News			alphatron Alpheidae Alpheus Alpheus River Alphonse Alphonse and Gaston Alphonse Bertillon Alphonse Daudet Alphonse De Candolle Alphonsine tables Alphonso Alphonso, Don Alphonsus Alphonsus Liguori, Saint alphorn Alpide Folding Alpide Geosynclinal Region Alpides alpine Alpine Belt Alpine Chough Alpine County alpine glacier Alpine Meadows Alpine orogeny Alpine permafrost alpine plants Alpine Riflemen Alpine Skiing alpine tundra Alpine Vegetation Alpine Weasel alpine-type facies Alpiniade alpinist alpinotype tectonics Alport's syndrome ALPR Alps Alps, Australian ALS Alsace Alsace-Lorraine Alsatia Alsatian Alsatians alsbachite Alsea Bay Historic Interpretive Center Alsen Alshvang, Arnold Alshvang, Arnold Aleksandrovich			Alpine High School Citizens Committee Alpine Hills Swimming Masters Alpine Historical Society Alpine horn Alpine horn alpine hulsea Alpine hut Alpine Ibex Alpine Iceman Alpine Kinderklinik Davos Alpine Laburnum Alpine Laburnum Alpine Laburnum Alpine lady fern Alpine Lady's-mantle Alpine Larch Alpine Leadership Pursuits for Skiers & Riders Alpine lift Alpine Line Alpine Line Alpine lodge Alpine Meadows Alpine Meadows National Ski Patrol alpine milk vetch Alpine mouse-ear Alpine nations Alpine nations Alpine orogeny alpine pasture deaths Alpine permafrost Alpine plant alpine plants Alpine Renault Club Limburg Alpine Renault Club Nederland Alpine Renault Gordini du Val de Saône Alpine Rescue Center Alpine Rescue Team Alpine resort Alpine Resort Board of Management Alpine Resort Management Board Alpine Riflemen alpine salamander Alpine scurvy Alpine sheep Alpine Ski Club Alpine Ski Nova Scotia Alpine skier Alpine skiing Alpine skiing Alpine skiing combined Alpine skiing combined Alpine Snow-Cover Analysis System Alpine Software Engineering Workshop Alpine Spruce Alpine Spruce Alpine States Alpine States alpine sunflower

Permafrost (redirected from Alpine permafrost)

permafrost

REFERENCES

Permafrost
(redirected from Alpine permafrost)