CGRG Bibliography of Canadian Geomorphology
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Author : Duk-Rrodkin, A.; and Barendregt, R.W.
Date : 2003.
Title : Plio-Pleistocene cordilleran and continental glaciations in northwest Canada.
Publication : Geoscience Horizons. 2003 Geological Society of America Annual Meeting & Exposition. November 2-5, 2003. Washington State Convention & Trade Center, Seattle, Washington.
Issue :
Page(s) :
Abstract
Northwest Canada and Eastern Alaska are recognized as having one of the oldest continental glacial records. Regional scale glaciations (Cordilleran and continental) commenced in northwest Canada and east-central Alaska between 2.9 and 2.6 Ma. Overall, two Cordilleran glaciations and two plateau ice caps (Horton Ice Cap) developed in the late Pliocene (Gauss and Matuyama Chron). During the early Pleistocene three Cordilleran glaciations are documented, while one to five continental glaciations (Keewatin Ice Sheet and Horton Ice Cap) are inferred from the Banks Island stratigraphic record (late Matuyama Chron). During the mid-Pleistocene (early Brunhes Chron), three Cordilleran glaciations are recorded (including the Reid Glaciation), as well as three continental glaciations (Keewatin Ice Sheet and Horton Ice Cap). During the late Pleistocene (late Brunhes) an extensive continental ice sheet (Keewatin) covered western and northwestern Canada while in the Yukon a much diminished Cordilleran ice sheet existed. Successive Cordilleran glaciations appear to have become progressively smaller while continental glaciations increased in size. The role of tectonics in the development of the two major physiographic barriers (Wrangell/St Elias Mountains and the Continental Divide (Mackenzie/Selwyn Mountains) appears to have been an important controlling variable in moisture distribution and ice sheet development in northwest Canada and east-central Alaska. New data from the Yukon, NWT, and Alaska has provided considerable refinement of ice sheet dimensions and timing of glaciations in Northwestern North America. The most complete terrestrial records of Late Cenozoic glaciations thus far, are obtained from sites along the Tintina Trench where multiple tills and paleosols record 7 polarity units, in the Klondike area where loess and glacial gravel sequences record 8 polarity units, and along the Yukon River near Fort Selkirk where Quaternary volcanics and interbedded glacial/interglacial sediments record at least 7 polarity units. Bore-core data from the Mackenzie Delta reveals at least 7 polarity units, and evidence for glaciations as early as the Gauss and Early Matuyama. The same is true for upland sites east of the delta (Horton River) where a record of several glacial units indicate that the earliest glaciation is of Gauss age
Bibliography of Canadian Geomorphology