Koppes, M.N., 2007, Glacier erosion and response to climate: From Alaska to Patagonia: University of Washington, Seattle, Ph.D. dissertation, vi, 233 p., illust. (some color), maps.
Contemporary glacial erosion rates based on sediment yields from tidewater glaciers in coastal Alaska and Patagonia are unsurpassed worldwide, and significantly exceed regional exhumation rates. These erosion rates are exceptionally high because the tidewater glaciers have been anomalously dynamic during a century of rapid retreat. To investigate the influence of climate and retreat on erosion, this dissertation presents seismic data defining the volume of sediments recently produced by one tidewater glacier in Southeast Alaska and two glaciers in Chilean Patagonia. These glaciers have all been in steady retreat during the 20th century, and all calve into a fjord, providing an efficient trap for the sediment delivered to the calving front. Using a model of proglacial sedimentation, the annual sediment yield from, and erosion rate of, each glacier are calculated. A strong correlation emerges between glacial retreat and sediment yields, implying that most contemporary sediment yield data from retreating tidewater glaciers may correspond to recent erosion rates that are a factor of 3.5 +/- 1.5 higher than over the entire advance-retreat cycle.
Theses and Dissertations