CGRG Bibliography of Canadian Geomorphology
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Author : Chouinard, C.; and Mareschal, J-C.
Date : 2007.
Title : 50000 years ground surface temperature histories inferred from temperature depth profiles in deep boreholes.
Publication : CMOS, CGU, AMS Congress 2007. "Air, Ocean, Earth and Ice on the Rock". May 28 - June 1, 2007. St. John's Congress Centre, Newfoundland and Labrador, Canada.
Issue :
Page(s) : C02-2B5 .8
Abstract
Several deep boreholes (>2000m) have been logged for temperature near Sudbury and Manitouwadge in Ontario. Thermal conductivity and radiogenic heat production measurements were made on core samples from the same holes. From these temperature depth profiles, the heat production, and the thermal conductivity data, we calculated the perturbations to the steady-state temperature regime. These perturbations are interpreted as caused by past temperature changes at the ground surface. We have used two different inversion techniques, one based on the singular value decomposition algorithm and the other based on a Monte Carlo search of parameter space to obtain a 50000 years ground surface temperature history (GSTH) for each region. We compare this GSTH with other GSTHs inferred from deep boreholes located in Central and eastern Canada to establish a spatial distribution of ground surface temperatures during the last glacial maximum (LGM) and the Holocene. Our analysis suggests that at LGM the temperatures were near 0°C at the base of the ice sheet throughout most of central Canada, and relatively colder (~ -5°C) near the eastern edge of the Laurentide glacier.
Bibliography of Canadian Geomorphology