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TitleCirque forms and alpine glaciation during the Pleistocene, west-central Yukon
AuthorNelson, F E N; Jackson, L E, Jr
SourceYukon Geology Program, Yukon Exploration and Geology 2002, 2003 p. 183-198 Open Access logo Open Access
LinksOnline - En ligne
Alt SeriesGeological Survey of Canada, Contribution Series 2002172
ProvinceNorthwest Territories; British Columbia; Yukon
NTS105E; 105F; 105G; 105J; 105K; 105L; 105M; 105N; 105O; 106B; 106C; 106D; 106E; 106F; 106G; 106J; 106K; 106L; 115A; 115B; 115C/01; 115C/02; 115C/07; 115C/08; 115C/09; 115C/10; 115C/15; 115C/16; 115F/01; 115F/02; 115F/07; 115F/08; 115F/09; 115F/10; 115F/15; 115F/16; 115G; 115H; 115I; 115J; 115K/01; 115K/02; 115K/07; 115K/08; 115K/09; 115K/10; 115K/15; 115K/16; 115N/01; 115N/02; 115N/07; 115N/08; 115N/09; 115N/10; 115N/15; 115N/16; 115O; 115P
Lat/Long WENS-141.0000 -130.0000 67.0000 61.0000
Subjectssurficial geology/geomorphology; glaciation; cirques; paleosols; glaciers; ice sheets; moraines; glacial landforms; glacial deposits; fluvial systems; Pleistocene
Illustrationslocation maps; geological sketch maps; graphs; aerial photographs; tables; photographs; bar graphs
ProgramFederal Public Sector Youth Internship Program
AbstractUplands in west-central Yukon supported alpine ice centres during the pre-Reid glaciations (Early Pleistocene). Subdued cirque forms are thought to be glacial cirques that have undergone degradation by nivation. The paleo-equilibrium line altitude (ELA) dropped as low as 1054 ± 96 m in the Crag Mountain upland (CMU). A pre-Reid age for the CMU cirques is based upon the presence of an Early-Middle Pleistocene paleosol in a moraine feature. Cirques in the Ogilvie Mountains provide proxy ELAs for the Reid (mean 1391 ± 132 m) and McConnell (mean 1488 ± 103 m) glaciations. Cirque glaciers did not form in CMU and most of Dawson Range during these later glaciations due to a decrease in precipitation. It is suggested that the progressive marginality of cirque glaciation through the Middle and Late Pleistocene may be related to the progressive enlargement of precipitation-diverting continental ice sheets east of the Cordillera.

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