GEOMETRY OF ORIENTED LAKES IN OLD CROW FLATS, NORTHERN YUKON

Pascale Roy-Leveillee, Christopher Burn

In the proceedings of: GeoQuébec 2015: 68th Canadian Geotechnical Conference & 7th Canadian Permafrost Conference

Session: John Ross MacKay Symposium - Permafrost II / Symposium John Ross MacKay - Pergélisol II

ABSTRACT: 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.

RÉSUMÉ: La plaine d™Old Crow est un basin intérieur parsemé de milliers de lacs thermokarstiques. Ces lacs sont de forme irrégulière lorsqu™ils sont entourés de fardoche et d™arbres qui peuvent rester enracinés malgré l™affaissement des berges, et qui empêchent ainsi l™érosion des sédiments sous-jacents. Dans la toundra, où le couvert végétal est facilement rompu, les vagues érodent et redistribuent les sédiments pour former des rivages rectilignes. La plupart de ces lacs sont parallèles aux vents dominants et ont une croissance accélérée dans cette direction, ce qui est contraire à la configuration des lacs de la plaine côtière de l™Arctique. Cette différence est due à la granulométrie fine des dépôts glacio-lacustres de la plaine d™Old Crow: très peu de sédiments sont suffisamment grossiers pour s™accumuler près des berges exposées au vent, laissant ces dernières vulnérables à l™action thermo-mecanique érosive des vagues.

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Cite this article:
Pascale Roy-Leveillee; Christopher Burn (2015) GEOMETRY OF ORIENTED LAKES IN OLD CROW FLATS, NORTHERN YUKON in GEO2015. Ottawa, Ontario: Canadian Geotechnical Society.

@article{284,author = Pascale Roy-Leveillee; Christopher Burn,title = GEOMETRY OF ORIENTED LAKES IN OLD CROW FLATS, NORTHERN YUKON,year = 2015}