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TitleSurficial geology and Holocene shoreline evolution near Whitebeach Point, Great Slave Lake, Northwest Territories
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AuthorO'Neill, H B; Wolfe, S A; Kerr, D E
SourceGeological Survey of Canada, Current Research (Online) 2019-3, 2019, 15 pages, https://doi.org/10.4095/314638 (Open Access)
Year2019
PublisherNatural Resources Canada
Documentserial
Lang.English
Mediaon-line; digital
File formatpdf (Adobe® Reader®)
ProvinceNorthwest Territories
NTS85J/06
AreaWhitebeach Point; Great Slave Lake
Lat/Long WENS-115.3333 -115.2333 62.4667 62.4000
Subjectssurficial geology/geomorphology; geophysics; geochronology; hydrogeology; economic geology; Holocene; glacial lakes; surface waters; lakes; sediments; beach sands; dunes; beach ridges; organic deposits; peatlands; glacial history; deglaciation; depositional history; shoreline changes; water levels; postglacial emergence; permafrost; ground ice; vegetation; hydrologic environment; geophysical surveys; radiometric dating; radiocarbon dating; mineral deposits; mineral potential; sand, commodity; fracturing sands; silica sands; remote sensing; photogrammetric surveys; groundwater; groundwater flow; sand wedges; Glacial Lake McConnell; Ancestral Great Slave Lake; glaciolacustrine beach sediments; eolian sediments; blowouts; LiDAR; geological mapping; forests; landscape development; elevations; digital elevation models; optically stimulated luminescence dating; colluvial and mass-wasting deposits; alluvial sediments; lacustrine sediments; lacustrine beach sediments; lacustrine littoral sediments; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; geoscientific sketch maps; profiles; tables; time series; photographs
ProgramMackenzie Corridor, North Bear Surficial Mapping, GEM2: Geo-mapping for Energy and Minerals
Released2019 09 10
AbstractDeposits of well sorted silica-rich beach sands occur along the western shore of Great Slave Lake around Whitebeach Point, Northwest Territories. Much of these deposits were windblown and redeposited following Holocene regression of glacial Lake McConnell and ancestral Great Slave Lake. Eolian deposits include active and stabilized sand sheets, transverse dunes, and localized blowouts. High-resolution lidar and optical imagery, combined with optical and radiocarbon dating, were used to derive a lake-level regression curve for the area, map the surficial geology and geomorphology, and reconstruct Holocene shorelines and landscape development. Lake water level was near the base of a limestone escarpment in the study area ca. 9.5 ka, about 60 m above the present lake level, and subsequently declined at a rate of about 2.3 mm a-1 from ca. 7.0 ka onward. Lake-level regression was accompanied by beach- and eolian-sand deposition in the form of incipient foredunes, primarily within a protected embayment. Permafrost occurs beneath land surfaces with thick (>30 cm) organic cover, including peatlands and densely forested areas, and likely affects the groundwater hydrology in the area. Permafrost is absent under sparsely vegetated eolian sand surfaces.
Summary(Plain Language Summary, not published)
Deposits of well-sorted beach sands occur along the western shore of Great Slave Lake around Whitebeach Point, NT. These deposits were deposited by wind after glacial Lake McConnell receded. Windblown deposits include active and stabilized sand sheets and dunes. We mapped the surficial geology and geomorphology and reconstructed Holocene shorelines and landscape development in the region. Lake water level was near the base of a limestone escarpment in the study area about 9,500 years ago, about 60 m above the present lake level, and then declined at a rate of ~2.3 mm per year from about 7,000 years ago onward. Lake-level regression was accompanied by beach and windblown sand deposition as parallel sand dunes within a protected embayment. Permafrost occurs beneath land surfaces with thicker organic cover, including peatlands and densely forested areas, and likely affects the groundwater hydrology in the area. Permafrost is absent under sparsely vegetated sand surfaces.
GEOSCAN ID314638