Umiujaq, northern Québec: innovative techniques to monitor the decay of a lithalsa in response to climate change

We describe the introduction of several new techniques to measure and monitor permafrost properties at a site near the east coast of the Hudson Bay, northern Québec. Eight boreholes were sunk through a lithalsa to the permafrost base. High precision temperature sensors and a pressure sensor were ins...

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Bibliographic Details
Published in:Permafrost and Periglacial Processes
Main Authors: Georg Delisle, Michel Allard, Richard Fortier, Fabrice Calmels, É. Larrivée
Format: Article in Journal/Newspaper
Language:unknown
Subjects:
Ice
Online Access:https://doi.org/10.1002/ppp.469
Description
Summary:We describe the introduction of several new techniques to measure and monitor permafrost properties at a site near the east coast of the Hudson Bay, northern Québec. Eight boreholes were sunk through a lithalsa to the permafrost base. High precision temperature sensors and a pressure sensor were installed in six boreholes to monitor the long‐time changes of the thermal field of the permafrost and internal pore pressure. Two open boreholes were used to carry out a ground penetrating radar transillumination survey to provide a tomographic image of the spatial distribution of electromagnetic wave velocities within the lithalsa. Cores taken from the permafrost below the active layer of the lithalsa show numerous oblique and fractured ice lenses indicative of extensive deformation of the lithalsa during its evolution. Examples of results of the new techniques applied in this study are provided. These techniques appear as very promising for permafrost studies in general. Copyright © 2003 John Wiley & Sons, Ltd.