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The influence of glacier change on sediment yield, Peyto Basin, Alberta, Canada.
Theodore John Mlynowski (author)Brian Menounos (Thesis advisor)University of Northern British Columbia (Degree granting institution)
Master of Science (MSc)
Number of pages in document: 101
The relation between sediment yield and glacier fluctuations at timescales less than a century remains uncertain. The primary goal of this study was to assess the influence of glacier activity on sediment yield within the Peyto Lake watershed. The research focused on a small alpine watershed in the Rocky Mountains of Alberta containing Peyto Glacier and the proglacial Peyto Lake. Using photogrammetric methods I determined changes in length, area, and volume of Peyto Glacier from a topographic survey map (1917) and 18 sets of aerial photographs (1947-2005). I also collected 18 sediment cores from Peyto Lake that consists of laminated, silt-clay couplets which can be shown through ¹³⁷Cs activity to be clastic varves. Varve thickness and sediment properties were combined to produce an annual record (1917-2010) of specific sediment yield (SSY) for the watershed. I then compared the SSY record to dimensional changes of Peyto Glacier as well as available mass balance records, hydrometric records, and climate records over the study period (1917-2010). Over the period 1917-2005, Peyto Glacier retreated 2198 ± 18 m, shrank 4.0 ± 0.9 km², thinned 44 ± 31 m, and lost 581 ± 404 x 10⁶ m³ water equivalent (w.e.). I measured an additional 85 ± 4 x 10⁶ m³ w.e. of ice loss from thinning ice-cored moraines adjacent to the glacier. Over the period 1917-2005 SSY averaged 446 ± 176 Mg km²yr⁻¹, which is among the highest measured yields in the Canadian Cordillera; however, this value is relatively low for glaciated basins worldwide. The SSY record has a poor relation to short-term dimensional changes of Peyto Glacier, likely due to the complexity of sediment transfers in proglacial environments. Long-term trends in SSY are hypothesized to arise from increasing (1870-1940) and decreasing (1970-2010) glacier contribution to streamflow over the past century.
Glaciers -- Climatic factors -- Peyto Glacier (Alta.)Sediments (Geology) -- Alberta -- Peyto Lake Watershed -- Analysis.Climatic changes -- Alberta -- Peyto Lake Watershed.