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INVESTIGATIONS OF DISCONTINUOUS PERMAFROST IN COASTAL LABRADOR WITH DC ELECTRICAL RESISTIVITY TOMOGRAPHY
Session: Geophysical Investigation in Cold Regions / Investigations géophysiques en milieu nordique
Robert Way, Department of Geography, University of Ottawa (Canada)
Antoni Lewkowicz, Department of Geography, University of Ottawa (Canada)
Investigations of ground conditions within the coastal Labrador communities of Cartwright (54°N) and Nain (57°N) revealed occurrences of discontinuous permafrost. The characteristics of permafrost bodies were examined using a combination of standard field methods and DC electrical resistivity tomography (ERT). In Cartwright, local climate is unfavourable for permafrost with mean annual air temperatures exceeding 0°C in recent years. Consequently, permafrost is thin (<6 m) and restricted to small palsa fields in raised bogs at exposed coastal locations. In the more northerly field area in Nain, permafrost was inferred to be present at numerous sites under both fine and coarse surficial covers. Permafrost up to 18 m thick was inferred in marine deposits at the coast and up to 9 m at a forested site. Despite challenges, a combination of standard field based methods and ERT can discriminate between frozen and unfrozen ground at these sites.
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