HR: 0800h
AN: H51E-0414    [Abstracts]
TI: Sediment Budget of a Post Little Ice Age Proglacial Lake in the Coast Mountains of British Columbia
AU: * Schiefer, E K
EM: schiefer@post.queensu.ca
AF: Queen's University, Deptartment of Geography, Mackintosh-Corry Hall, Room D201, Kingston, ON K7L 3N6 Canada
AU: Gilbert, R
EM: Robert.Gilbert@queensu.ca
AF: Queen's University, Deptartment of Geography, Mackintosh-Corry Hall, Room D201, Kingston, ON K7L 3N6 Canada
AB: A sediment budget approach is used to investigate upland sediment sources, storage, and yield in a highly-dynamic, glaciated lake catchment. Lillooet Glacier, the largest valley glacier in the southern Coast Mountains, has retreated over 6 km from its Little Ice Age maximum of the late 19th century. The glacier has been highly sensitive to contemporary climatic warming due to the low elevation of the glacier terminus (<800 m.a.s.l.) and control of mass balance by both maritime and continental climatic influences. Glacial retreat between 1947 and 1965 exposed a 1.0 km² lake at the terminus. By 2005 the glacier retreated a further 3 km upvalley and the lake surface area decreased to less than half of its original size due to exceptionally high rates of sediment accummulation. Decadal rates of glacier recession, proglacial sediment erosion, floodplain aggradation, and delta progradation are assessed from large-scale aerial photographs (1947-1999). Process studies in the lake and its surroundings along with varved deposits recovered from the lake floor document the annual record of sediment accumulation, and indicate the importance of extreme events such as autumn floods. This study contributes to sediment budget research in the lower Lillooet valley and suggests that upland sediment production from contemporary glaciers and Neoglacial deposits has been previously underestimated.
DE: 1815 Erosion
DE: 1817 Extreme events
DE: 1824 Geomorphology: general (1625)
DE: 1861 Sedimentation (4863)
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: Fall Meeting 2005