Permafrost: distribution and relation to environmental factors in the Hudson Bay lowland
The Hudson Bay Lowland lies mostly in the permafrost region of Canada. The distribution of permafrost varies from discontinuous in the southeast, north of the 30 degree F mean annual air isotherm, to continuous in the northwest, between the 25 degree F and 20 degree F mean annual air isotherms. The...
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
1973
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| Online Access: | https://nrc-publications.canada.ca/eng/view/ft/?id=de2095a3-557b-4bd5-8474-5a00f2a398b6 https://nrc-publications.canada.ca/eng/view/object/?id=de2095a3-557b-4bd5-8474-5a00f2a398b6 https://nrc-publications.canada.ca/fra/voir/objet/?id=de2095a3-557b-4bd5-8474-5a00f2a398b6 |
| Summary: | The Hudson Bay Lowland lies mostly in the permafrost region of Canada. The distribution of permafrost varies from discontinuous in the southeast, north of the 30 degree F mean annual air isotherm, to continuous in the northwest, between the 25 degree F and 20 degree F mean annual air isotherms. The active layer varies from 1 to 3 feet, and permafrost ranges in thickness from a few inches at the southern limit to 200 feet in the continuous zone at Churchill. In the discontinuous zone, permafrost is found in peat plateaus and palsas which are prevalent, but it does not occur in intervening wet depressions nor in beach ridges or river banks. Permafrost exists everywhere beneath the land surface in the continuous zone which forms a narrow strip along the Hudson Bay coast. The most distinctive permafrost features are palsas of varying size to elevated peat plateaus exceeding 10 feet in height covering several acres. They form very distinctive air photo patterns and their origin appears related to thin snow cover. Le bas-pays de la Baie d'Hudson se trouve largement à l'intérieur de la région de pergélisol canadienne. La distribution du pergélisol varie entre la zone discontinue dans le sud-est, au nord de l'isotherme annuel moyen de l'air de 30 degrés F, et la zone continue dans le nord-ouest, entre les isothermes annuels moyens de l'air de 25 et de 20 degrés F. La couche active varie entre 1 et 3 pieds et l'épaisseur du pergélisol entre quelques pouces (limite sud) et 200 pieds (zone continue à Churchill). Dans la zone discontinue, le pergélisol se trouve dans les plateaux tourbeux et les palses, que prédominent, mais non dans les dépressions humides intermédiaires ni dans les levées de plage ou les bancs fluviaux. On trouve le pergélisol partout sous la surface terrestre dans la zone continue qui forme une mince lisière le long de la Baie d'Hudson. Les traits les plus distinctifs du pergélisol sont les palses de grandeurs différentes allant jusqu'à des plateaux tourbeux élevés de plus de 10 pieds et couvrant ... |
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