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GEOMETRY OF ORIENTED LAKES IN OLD CROW FLATS, NORTHERN YUKON
Session: John Ross MacKay Symposium - Permafrost II / Symposium John Ross MacKay - Pergélisol II
Pascale Roy-Leveillee, Laurentian University (Canada)
Christopher Burn, Carleton University (Canada)
Old Crow Flats is an interior basin with thousands of thermokarst lakes. These lakes have irregular shapes where they are surrounded by trees and tall shrubs that may remain rooted after bank subsidence and protect the underlying sediment from erosion. In polygonal tundra, the vegetation cover is easily removed and wave action can erode and redistribute bank sediment to form rectilinear shores. The majority of lakes with rectilinear shores are aligned parallel to dominant winds and expand most rapidly in this direction. This is contrary to the oriented lakes of the Arctic coastal plain and is due to the fine texture of glacio-lacustrine deposits in OCF, which contain very little sediment sufficiently coarse to accumulate near-shore along the leeward side of the lake, leaving the bank vulnerable to thermo-mechanical erosion caused by wave action.
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