ENVS 2160 Lecture Notes - Lecture 21: Frost Heaving, Subsidence, Patterned Ground
22 Jun 2016
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Periglacial pertaining to processes, conditions, areas, climates, and topographic features occurring near glaciers and ice sheets, and influenced by the cold temperature of the ice. Permafrost ground, soil, or rock that remains at or below 0c (below freezing) for at least two years (fig 10. 6) Continuous permafrost ground temperature range from ~-5 - -12c and the material below the active layer is perennially frozen everywhere throughout the year (except maybe beneath bodies of water) Discontinuous permafrost patches of unfrozen ground during the summer, surround by frozen areas with average ground temps of -1 - -4c (permafrost occurs in some places but not others) Sporadic permafrost area near the southern boundary of discontinuous permafrost where permafrost occurs in isolated patched. Distribution of permafrost in north america (fig french, 1997) Permafrost thickest in well-drained sandy and gravelly and bedrock areas where there"s no insulation by organic matter and thermal conduction values are high (fig 10. 9)
