Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stumpf, A. J. Articles by Levson, V. M. Search for Related Content GeoRef GeoRef Citation

Multiphase flow of the late Wisconsinan Cordilleran ice sheet in western Canada

¹ Quaternary and Environmental Studies Group, Department of Geology, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick E3B 5A3, Canada
² British Columbia Ministry of Energy and Mines, Geological Survey Branch, P.O. Box 9320 STN PROV GOVT, Victoria, British Columbia V8W 9N3, Canada

In central British Columbia, ice flow during the late Wisconsinan Fraser glaciation (ca. 25–10 ka) occurred in three phases. The ice expansion phase occurred during an extended period when glaciers flowed westward to the Pacific Ocean and east-southeastward onto the Nechako Plateau from ice centers in the Skeena, Hazelton, Coast, and Omineca Mountains. Initially, glacier flow was confined by topography along major valleys, but eventually piedmont and montane glaciers coalesced to form an integrated glacier system, the Cordilleran ice sheet. In the maximum phase, a Cordilleran ice divide developed over the Nechako Plateau to 300 km inland from the Pacific coast. At this time, the surface of the ice sheet extended well above 2500 m above sea level, and flowed westward over the Skeena, Hazelton, and Coast Mountains onto the continental shelf, and eastward across the Rocky Mountains into Alberta. In the late glacial phase, a rapid rise of the equilibrium line caused ice lobes to stagnate in valleys, and restricted accumulation centers to high mountains.

Discordant directions in ice flow are attributed to fluctuations of the ice divide representing changes in the location of accumulation centers and ice thickness. Ice centers probably shifted in response to climate, irregular growth in the ice sheet, rapid calving, ice streaming, and drainage of proglacial and subglacial water bodies. Crosscutting ice-flow indicators and preservation of early (valley parallel) flow features in areas exposed to later (cross-valley) glacier erosion indicate that the ice expansion phase was the most erosive and protracted event.

Key Words: Cordilleran • divides • ice flows • ice sheet • Quaternary • western Canada

This article has been cited by other articles:

				R. Hetherington, A. J. Weaver, and A. Montenegro Climate and the migration of early peoples into the Americas Geological Society of America Special Papers, January 1, 2007; 426(0): 113 - 132. [Abstract] [Full Text] [PDF]

				J. E. Dixon, J. R. Filiberto, J. G. Moore, and C. J. Hickson Volatiles in basaltic glasses from a subglacial volcano in northern British Columbia (Canada): implications for ice sheet thickness and mantle volatiles Geological Society, London, Special Publications, January 1, 2002; 202(1): 255 - 271. [Abstract] [PDF]