CGRG Bibliography of Canadian Geomorphology
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Author : Barrie, J.V. and Conway,K.W.
Date : 1995
Title : Rapid Coastal Zone Evolution - Queen Charlotte Islands
Publication : The Canadian Coastal Conference 1995 Dartmouth, Nova Scotia
Issue :
Page(s) :
Abstract
The coast of the Queen Charlotte Islands off the Pacific margin of Canada has been changing under the influence of isostasy, eustacy, tectonics and sediment transport since the late Quaternary. Progradation rates of 0.3 to 0.5 m/year have been calculated along the north beach (40 km) while coastal bluff retreat on the entire 120 km of east beach, determined from beach profiles and repetitive aerial photography, is estimated to be between l and 3 m/year with up to 1.5 m of coastline observed to retreat in 24 hours during winter storms. At the junction of these two systems is Rose Spit, which extends northeastward at a point of sediment transport convergence. Historical bathymetric data and aerial photographs indicate that a spit platform seaward of the present spit has extended 10 km to the northeast and at least four portions of the platform bank have become emergent since 1911. The area is seismically active, being near the boundary of the Pacific and North American plates, and subject to storm-related sediment transport events superimposed on strong semi-diurnal tidal flows (5m tidal range). The development of a spit platform, the emergence of the offshore bars and the net coastal changes are primarily controlled by: 1) convergence of sediment transport between the waters of Hecate Strait to the south and Dixon Entrance to the north and 2) localised tectonic uplift due to transpressional folding in this area east of the Queen Charlotte Fault. These dramatic sediment transport and sea level conditions result in a coastline that is in constant change.
Bibliography of Canadian Geomorphology