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. Tundras, 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.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on permafrost from Fact Monster:

  • Major Biomes of the World - Major Biomes of the World Have you visited any biomes lately? A biome is a large ecosystem where ...
  • Yamalo-Nenets Autonomous Area - Yamalo-Nenets Autonomous Area Yamalo-Nenets Autonomous Area , administrative division (1995 pop. ...
  • climate: Primary Influence on Climate - Primary Influence on Climate The major influence governing the climate of a region is its latitude. ...
  • subsidence - subsidence subsidence, lowering of a portion of the earth's crust. The subsidence of land areas ...
  • tundra - tundra tundra , treeless plains of N North America and N Eurasia, lying principally along the ...

See more Encyclopedia articles on: Geology and Oceanography