CGRG Bibliography of Canadian Geomorphology
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Author : Clague, J.J.; Brahney, J.; Luckman, B.H.; Edwards, T.W.D.; Menounos, B.; Gilbert, R.; Froese, D.; Jensen, B.J.L.; and Reyes, A.V.
Date : 2009
Title : The ups and downs of Kluane Lake during the late Holocene.
Publication : CANQUA–CGRG Biennial Meeting. May 3-8, 2009. Simon Fraser University, Burnaby Campus, Burnaby, British Columbia.
Issue : Programme and Abstracts Volume
Page(s) : 57.
Abstract
We reconstructed late Holocene fluctuations of Kluane Lake, the largest lake in Yukon Territory, using (1) tree-ring and radiocarbon ages on in situ drowned trees and driftwood and (2) variations in bulk physical properties and elemental and isotopic abundances in nine lake-bottom sediment cores. Elements associated with organic material and oxyhydroxides were used to reconstruct redox fluctuations in the hypolimnion of the lake. The diverse data show that Kluane Lake fluctuated within a narrow range, at levels about 25 m below the present datum, from about 5000 to 1300 years ago. Low lake levels during this interval are probably due to southerly drainage of Kluane Lake to the Pacific Ocean, opposite the present northerly drainage to Bering Sea. Slims River, which today is the largest contributor of water to Kluane Lake, only rarely flowed into the lake between 5000 and 1300 years ago. A period of influx of sediment via Duke River at the north end of the lake coincides with a relatively warm climate around 1300 years ago. At times when neither Slims River nor Duke River discharged into Kluane Lake, the level of the lake was low and stable thermal stratification developed, with anoxic and possibly euxinic conditions in the hypoliminion. Kluane Lake rose 7-12 m between 1300 and 900 cal yr BP, reached its present level around AD 1650, and within a few decades had risen an additional 12 m. Shortly thereafter, the lake established a northern outlet and fell to near its present level. It has fluctuated within a range of about 3 m over the past 50 years. The data support the hypothesis of Hugh Bostock, who suggested in 1969 that the maximum Little Ice Age advance of Kaskawulsh Glacier deposited large amounts of sediment in the Slims River valley and established the present course of Slims River into Kluane Lake. Bostock argued that these events caused the lake to rise and eventually overflow to the north. The overflowing waters incised the Duke River fan at the north end of Kluane Lake and lowered the lake to its present level. This study highlights the potentially dramatic impacts of climate change on regional hydrology during the Little Ice Age in glacierised mountains.
Bibliography of Canadian Geomorphology