CGRG Bibliography of Canadian Geomorphology
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Author : Forbes, D.L.; Bell, T.; Craymer, M.; and Manson, G.
Date : 2004.
Title : Coastal submergence and emergence across the Canadian Arctic.
Publication : Arctic Net. First Annual Scientific Meeting, Palace Royal, Quebec City. December 5-8, 2004. Program.
Issue :
Page(s) : 29.
Abstract
Geological data on postglacial relative sea-level (RSL) change in the Canadian Arctic demonstrate strong east-west gradients from the Beaufort Sea to Baffin Bay. Conditions range from ongoing emergence in the central archipelago to bands of submergence extending along the eastern fringe of Baffin and Bylot Islands and the outer Arctic coast from the Beaufort Sea north to Prince Patrick Island or beyond. This pattern is broadly consistent with the distribution of vertical isostatic adjustment in viscoelastic geophysical models. We have recently established three networks for measuring present rates of vertical motion and coastal submergence or emergence: • epoch GPS sites at Mould Bay (Prince Patrick Island), Cape M’Clure and Mercy Bay (Banks Island), Kugluktuk (Coronation Gulf coast of Nunavut), and Iqaluit (Baffin Island); • continuous GPS (CGPS) sites at Resolute (Cornwallis Island), Sachs Harbour (Banks Island), and Inuvik (adjacent to Mackenzie Delta); and • additional CGPS stations co-located with tide gauges at Alert (Ellesmere Island), Qikiqtarjuaq (Baffin Island), Holman (Victoria Island), and Tuktoyaktuk (Beaufort Sea mainland coast). In addition to studies of present trends, geomorphological analysis and marine geological surveys provide data on the elevations of past shorelines above and below present sea level, contributing to an understanding of regional isostatic adjustment during and after the Last Glacial Maximum. In the western Arctic, geomorphic evidence of recent submergence is seen from the Yukon coast east to Victoria Island and north to Mackenzie King Island. Diagnostic features include river-mouth embayments, breached lake basins, submerged icewedge polygon terrain, transgressive beach and barrier systems, and prograded beach-ridge sequences rising seaward, among others. These data provide an opportunity to test model estimates of RSL trends in the context of climate warming and regional sea-level rise over coming decades. Of particular interest is the transition zone between present submergence and emergence, where accelerated sea-level rise may lead to eastward expansion of the zone of submergence. Extensive barrier washover or storm-surge flooding and associated shore erosion at sites such as Kugluktuk and Iqaluit attest to the potential for storm reworking of shorelines even in areas of ongoing emergence, but may also indicate a situation close to transition. This is one aspect of coastal stability that will receive more attention as part of Project 1.2 in ArcticNet.
Bibliography of Canadian Geomorphology