CGRG Bibliography of Canadian Geomorphology
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Author : Burn, C.R.
Date : 1992
Title : Recent ground warming inferred from the temperature in permafrost near Mayo, Yukon Territory.
Publication : Periglacial Geomorphology. Edited by: J.C. Dixon and A.D. Abrahams. Chichester: John Wiley and Sons Ltd.
Issue :
Page(s) : 327-350
Abstract
Mayo, Yukon Territory, lies in the widespread discontinuous permafrost zone. Nearby, permafrost thicknesses of up to 40 m have been measured in valleys, and of up to 135 m at higher elevations. Ice-rich glaciolacustrine sediments near Mayo, in which permafrost is 34 m thick, show evidence of recent warming. The mean annual ground temperature at the depth of zero annual amplitude (10 m) is -1.3°C. At present temperatures are slightly warmer, between 0 and 5 m, almost constant between 5 and 15 m, and then increase in depth. Upward projection of the temperature gradient at depth suggests a former mean temperature at the surface of permafrost of at most -2.0°C. The ground is close to the temperature at which the unfrozen water content characteristic begins to change during warming, indicating that some ices is thawing in the soil. Geothermal modelling suggests that if ground temperatures were previously in equilibrium with a near-surface temperature of approximately -3.0°C, then it has taken about 20 years for permafrost to reach present conditions. Observed changes in mean winter temperature and snowfall have probably caused the ground warming.
Bibliography of Canadian Geomorphology