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TitleQuaternary geology of Fort Liard map area, Northwest Territories
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AuthorBednarski, J M
SourceGeological Survey of Canada, Bulletin no. 596, 2008, 59 pages; 1 CD-ROM, https://doi.org/10.4095/225608
Year2008
PublisherNatural Resources Canada
Documentserial
Lang.English
Maps1 map
Map Info.surficial geology, glacial deposits and features, 1:50,000
Mediapaper; CD-ROM; digital; on-line
RelatedThis publication is related to the following publications
File formatpdf (Adobe® Reader®)
ProvinceNorthwest Territories
NTS95B
AreaCelibeta Lake; Fort Liard; Liard River
Lat/Long WENS-124.0000 -122.0000 61.0000 60.0000
Subjectssurficial geology/geomorphology; stratigraphy; glacial deposits; organic deposits; colluvial deposits; alluvial deposits; lacustrine deposits; eolian deposits; glaciolacustrine deposits; glaciofluvial deposits; tills; glacial features; glacial landforms; moraines; eskers; glacial history; bedrock geology; physiography; drift deposits; glacial stages; ice movement; ice retreat; ice transport directions; ice movement directions; sands; gravels; peatlands; permafrost; landslides; grain size analyses; Wisconsinan Glaciation; Laurentide Ice Sheet; Quaternary; Cenozoic
Illustrationslocation maps; photographs; tables; ternary diagrams; photomicrographs
Released2008 12 22
AbstractDetailed mapping of the surfi cial geology of the Fort Liard area (NTS 95 B) provides insight into the dynamics of the Laurentide Ice Sheet as it impinged against the Cordilleran Ice Sheet during the last glacial maximum. Overall, ice advance over the plains was from the northeast, but as the ice sheet approached the mountain front, the fl ow was defl ected southward, up the lower Liard River valley. In the southern part of the map area, curving fl owlines record the collision and northward defl ection of the Laurentide Ice Sheet when it impinged on the Cordilleran Ice Sheet in the mountains west of the map area. High-elevation striations and Canadian Shield erratics show that the entire region was glaciated during this time. Once deglaciation began, an expanding corridor between the two ice sheets was instrumental in channelling meltwater from at least 500 km of the Laurentide ice margin, northward, into the Mackenzie Basin. During early deglaciation, drainage divides connecting northward-trending mountain valleys controlled proglacial lakes levels (>600 m a.s.l.). With eastward retreat of the Laurentide ice margin, glacial lake levels continued to fall as lower outlets became ice-free. About 11.5 ka BP, a large glacial lake formed in Liard River valley when the Laurentide ice margin disengaged from the mountain front. The entire map area was deglaciated shortly after 11 ka BP. Glacial Lake Liard fi nally drained into Mackenzie River valley when the ice margin retreated east of the confl uence of the Liard and Mackenzie rivers.
GEOSCAN ID225608