The influence of terrain factors on the distribution of permafrost bodies in the Chic-Choc Mountains, Gaspesie, Quebec
| Autor: | Gray, J. T., Brown, R. J. E. |
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| Jazyk: | angličtina |
| Rok vydání: | 1982 |
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| Popis: | Ground temperature studies revealed the presence of several contemporary bodies of discontinuous permafrost on the windswept treeless summits of the Chic-Choc Mountains in Gaspe|'sie. One such permafrost body on Mont Jacques- Cartier is 45 to 60 m thick and related to a mean annual ground surface temperature of -1 to -1.5 degrees C. Snow cover is the principal terrain factor governing the presence or absence of permafrost. Snow depth indices derived from long-term data from a similar climatic region in central Que|'bec-Labrador permitted the Mont Jacques-Cartier permafrost to be plotted on the basis of snow cover. The rapid increase in snow depth as one crosses from the tundra into the krummholz zone enabled a close correlation to be made between the permafrost boundary and the tree-line. This correlation is not perfect, however. First, local tree- lines occur below the critical altitude at which the mean annual air temperature is sufficiently low to induce the development of permafrost, either due to local lithologic, microclimatic, or geomorphological conditions. Secondly, in the tundra zone large topographic hollows on the leeward side of summits harbour a deep winter snow pack which inhibits permafrost development. Thirdly, below the regional tree-line, lenses of permafrost occur in rock glaciers at the base of steep slopes. Fourth Canadian Permafrost Conference, March 2, 1981, Calgary, Alberta, Canada |
| Databáze: | OpenAIRE |
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