Climate and Permafrost 43 Cryogenetic mounds as indicators of permafrost conditions, northern QuCbec
Along the east coast of Hudson Bay, palsas and related cryogenic mounds are easily discernable evi-dence of the presence of permafrost. Analysis of their distribution shows a zonation oriented NE-SW, approximately parallel to the shore. In the first zone, within 20 km of the shore and mainly north o...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.560.4290 http://pubs.aina.ucalgary.ca/cpc/cpc4-43.pdf |
| Summary: | Along the east coast of Hudson Bay, palsas and related cryogenic mounds are easily discernable evi-dence of the presence of permafrost. Analysis of their distribution shows a zonation oriented NE-SW, approximately parallel to the shore. In the first zone, within 20 km of the shore and mainly north of Richmond Gulf, peat-bogs are scarce and mineral cryogenic mounds occur in most locations where surficial deposits exist. In the second zone, peatzbogs are more widespread and permafrost is found both in surficial deposits (mineral cryogenic mounds) and peat-bogs (palsas). South of 56 " N, towards the interior, string-bogs are the dominant type of peat-bogs, with occasional partially collapsed palsas. Permafrost has been more widespread in the region in the recent past, and its extent is now decreas-ing. In areas of discontinuous permafrost such as that of the study, the distribution of palsas and related cryogenic mounds is a good indicator of the extent and general conditions of permafrost. Sur le littoral Est de la Mer d'Hudson les palses et autres buttes cryogtnes sont les evidences les plus nettes de la presence de pergelisol. L'analywde leur distribution montre une zonation en bandes orientee NE-SW, plus ou moins paralltles au rivage. Dans la premitre bande, large d'environ 20 km a partir du littoral, et au Nord du Golfe de Richmond, les tourbikres sont rares et les buttes cryogtnes minerales sont presentes partout ou il y a des dtpBts de surface. Dans la deuxieme, les tourbitres sont plus repandues et le pergelisol se rencontre a la fois dans les terrains mineraux et dans les tourbikres. Au Sud du 56kme paralltle, les tourbikres rCticulCes dominent avec qa et la des palses plus ou moins dkgradtes. L'extension du pergClisol a CtC plus grande dans un passe rkent dans la region etudite. Elle decroit maintenant comme c'est le cas pour la plus grande partie du Nouveau-Quebec. Dans la zone du pergelisol discontinu, il apparait donc que les buttes cryogknes, considtrkes en tant qu'ensemble et non individuellement, ... |
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