CGRG Bibliography of Canadian Geomorphology
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Author : Bell, T.; St. Hilaire, D.; Brucker, S.; Hughes Clarke, J.; Danielson, B.; Sharp, M.; and Tarasov, L.
Date : 2006.
Title : Seabed mapping at the terminus of Belcher Glacier, Devon Island, Nunavut.
Publication : 3rd Annual ArcticNet Scientific Meeting. December 12-15, 2006. Victoria, British Columbia.
Issue : Abstracts Volume
Page(s) : 28.
Abstract
The seabed at the terminus of Belcher Glacier, a tidewater glacier draining the northeastern sector of the Devon Ice Cap, was the focus of bathymetric mapping and subbottom profiling using multibeam and acoustic technologies during Leg 1 of the NGCC Amundsen cruise in September 2006. The research is part of the Canadian contribution to the IPY project Glaciodyn: the Dynamic Response of Arctic Glaciers to Global Warming, which has as its goal to investigate the role of ice dynamics in the response of Arctic glaciers and ice caps to global warming. Tidewater glaciers are a particular focus of Glaciodyn because of the influence of meltwater production on ice velocities and consequently calving rates (the recent dramatic increase in the rate of mass-loss for the Greenland Ice Sheet is a case in point). Belcher Glacier, Canada's field site for Glaciodyn, is the largest and fastest flowing (up to 300 m yr-1) outlet of the Devon Ice Cap, and it terminates in about 300 m of tidewater. Glacier flow is largely by basal sliding and/or bed deformation. The glacier may be susceptible to hydrologically-driven velocity variations, as it has a well-developed surface drainage system linked to englacial and subglacial conduits via crevasse fields. The glacier bed lies below sea level in the lower 11 km of the glacier and reaches 400 m below sea level in an over-deepened basin located 2-5.5 km from the terminus. Belcher Glacier accounts for approximately half the iceberg calving loss from Devon Ice Cap and its bed topography suggests that its terminus region could become unstable in the event of further retreat. It is thus well suited for a study on the dynamic response of tidewater glaciers to global warming. Seabed mapping off the terminus of Belcher Glacier is one part of a targeted field program, which will link to remote sensing and modeling components. The 2006 mapping program was carried out over a 12-hour period and consisted of: i) imaging of deeper parts of the inlet using the EM300 30 kHz multibeam and 3.5 kHz subbottom profiler on the NGCC Amundsen; and ii) detailed mapping adjacent to the tidewater front using the 300 kHz multibeam and 3.5 kHz subbottom profiler on the hydrographic launch CSL Heron. This poster presents the first information on the bathymetry, geomorphology and marine geology of the inlet in front of Belcher Glacier and the seabed extending out into Lady Anne Strait. Features such as De Geer moraines and flutings record previous positions of the grounding line and basal sliding of the grounded glacier beyond its current terminus, respectively. Historical aerial photography and more recent satellite imagery provide an opportunity to relate former ice-front positions to grounding lines and seabed geology. Seabed furrows and scours record the calving and movement of icebergs at the terminus. Future research will extend multibeam mapping coverage, retrieve sediment cores for palaeo-environmental analyses, and extend temporal coverage of CTD profiling to better assess oceanographic interactions with the calving front.
Bibliography of Canadian Geomorphology