| Abstract/Description or Keywords |
Episodic growth and decay of the Cordilleran ice sheet during the Pleistocene has imposed order on Quaternary stratigraphies in British Columbia and southern Yukon Territory. Although Quaternary deposits in this region are inherently complex, thick valley and lowland fills consist of discrete packages of glacial sediments separated by unconformities or by generally thin, patchy interglacial deposits. Some unconformities define former valley and lowland landscapes of similar relief to the present. Each package of glacial sediments displays stratigraphic order: distinctive fluvial and lacustrine units, deposited during the early stage of a glaciation and later overridden and eroded by glaciers, are overlain by retreat phase and interglacial fluvial, lacustrine, and marine sediments. Packages of glacial sediments contain one or more unconformities produced by glacial erosion; commonly the unconformities are better stratigraphic markers than tills, which are not always present, especially in valleys |
