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TitleGlacial dispersal and flow history, East Arm area of Great Slave Lake, NWT, Canada
AuthorSharpe, D R; Kjarsgaard, B A; Knight, R D; Russell, H A J; Kerr, D E
SourceQuaternary Science Reviews no. 165, 2017 p. 49-72, https://doi.org/10.1016/j.quascirev.2017.04.011 (Open Access)
Year2017
Alt SeriesNatural Resources Canada, Contribution Series 20180126
PublisherElsevier BV
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNorthwest Territories
NTS75E; 75F; 75G; 75H; 75I; 75J; 75K; 75L; 75M; 75N; 75O; 75P
AreaGreat Slave Lake; East Arm; Thaidene Nëné National Park Reserve
Lat/Long WENS-112.0000 -104.0000 64.0000 61.5000
Subjectssurficial geology/geomorphology; economic geology; geochemistry; mineralogy; glacial history; glaciation; deglaciation; ice flow; glacial erosion; sediment transport; sediment dispersal; dispersal patterns; glacial deposits; glacial landforms; glacial features; tills; eskers; hummocks; moraine, ribbed; drumlins; boulders; glacial striations; crag and tail; roches moutonnees; mineral deposits; mineral potential; mineral exploration; exploration methods; pebble lithology; sandstones; mineralogical analyses; chromite; models; permafrost; periglacial features; patterned ground; mud boils; ice-wedge polygons; Laurentide Ice Sheet; Keewatin Ice Divide; Barrenlands Group; Thelon Basin; Slave Craton; Thelon Tectonic Zone; East Arm Basin; Taltson Magmatic Zone; Rae Domain; M'clintock Ice Divide; ice-flow directions; glaciofluvial sediments; esker sediments; till veneer; hummocky tills; till blanket; indicator minerals; s-form erosion; subglacial meltwater corridors; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; geoscientific sketch maps; photographs; profiles; tables; schematic models
ProgramGeomapping for Energy & Minerals (GEM) - Program Coordination, GEM: Geo-mapping for Energy and Minerals
Released2017 04 25
AbstractLittle work has been completed on paleo-ice-sheet flow indicators of the Laurentide Ice Sheet, west of the Keewatin Ice Divide. Field mapping, sampling and analysis of glaciogenic sediment (~500 sample sites) in a ~33,000 km2 region near the East Arm of Great Slave Lake in northwestern Canada, provided a rare opportunity to improve understanding of sediment erosion and transport patterns. Glacially-eroded bedrock and sedimentary landforms record east to west flow with NW and SW divergence, mapped within a portion of the Great Slave Lake flow tract. Transported till reflects a similar divergent flow pattern based on dispersal geometries for multiple indicators (e.g., heavy minerals and lithic fragments), which are aligned with the dominant and latest ice flow direction. Glaciofluvial erosion (e.g., s-forms and till removal), transport, and deposition (mainly as esker sediment) are set within 0.3 - 3 km wide meltwater erosional corridors, spaced regularly at 10 - 15 km intervals. Transport paths and distances are comparable in till and esker sediment, however, distances appear to be greater (~5 - 25 km) in some esker constituents and indicator minerals are typically more concentrated in esker sediment than in till. Corridors form a divergent array identical to the pattern of ice-flow features. The congruence of ice and meltwater flow features is interpreted to be a response to a similar ice sheet gradient, and close timing of events (late dominant glacial ice flow and meltwater flow).
The similarity in glacial and glaciofluvial flow patterns has important ramifications for event reconstruction and for exploration geologists utilizing mineral and geochemical tracing methods in this region, and possibly other parts of northern Canada. The correspondence between East Arm dispersal patterns, landforms and flow indicators supports interpretation of a simple and predictable single flow divergence model. This is in contrast to previous, multi-flow models, in which fan-shaped geometries are often reported to result from multiple transport events, compared to single-flow divergence. The observed widespread effects of glaciofluvial processes (e.g., erosional corridors) indicate a need to update existing terrain process models.
Summary(Plain Language Summary, not published)
Study of a ~33,000 km2 region near the East Arm of Great Slave Lake was carried out to support regional mineral assessment. Erosional and sedimentary landforms record east to west flow with NW and SW radial divergence across the study area, as do the dispersal geometries for most indicator minerals. The apparently simple observed dispersal pattern is consistent with a single dominant flow and with evidence of latest ice and meltwater flow directions. The divergent geometry for most East Arm landforms is in correspondence with a regional flow tract that extends from Keewatin Ice Divide to west of Great Slave Lake. The similarity in glacial and glaciofluvial flow patterns has important ramifications for exploration geologists utilizing mineral and geochemical tracing methods. The correspondence between East Arm dispersal indicators, landforms and flowline tracts supports interpretation of a simple and predictable setting for mineral exploration using glaciogenic sediments.
GEOSCAN ID308390