CGRG Bibliography of Canadian Geomorphology
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Author : Harris, S.A.
Date : 1982
Title : Distribution of zonal permafrost landforms with freezing and thawing indices.
Publication : Biuletyn Peryglacjalny
Issue : 29:
Page(s) : 163-182
Abstract
In areas with under 50 cm snow cover in winter, the permafrost zones can be defined by freezing indices and thawing indices. The relationship works for Norway, Spitsbergen, Canada and Mongolia, and since these include a very wide range of thermal environments, it is possible to trace the thermal ranges of the various active periglacial landforms. The zone of continuous permafrost markedly transgresses the isotherms of mean annual air temperature and is delimited by the area of Holocene felsenmeer and ice wedge polygons in mineral soils. Active ice wedges in peats, contraction cracks in mineral soils, the earth hummocks of arctic Canada, and cemetery mounds of Siberia, non-sorted polygons and open system pingos extend into the zone of discontinuous permafrost. Sorted polygons and closed system pingos extend even further. Palsas, peat plateaux and ice caves extend from the zone of continuous permafrost into that of sporadic permafrost in Norway and Quebec, while ice-cored string bogs and thufurs occur in both the discontinuous and sporadic permafrost zones. Rate of growth and longevity of the palsas depend on the climatic zone.
Bibliography of Canadian Geomorphology