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TitleTill composition and glacial dispersal patterns in South Rae Craton, Northwest Territories
AuthorLauzon, G; Campbell, J E; Dyke, A S; Pehrsson, S J
Source2016 Yellowknife Geoscience Forum, abstract and summary volume; by Irwin, D; Gervais, S D; Terlaky, V; Northwest Territories Geological Survey, Yellowknife Geoscience Forum Abstracts Volume 2016, 2016, 91-92 pages
Alt SeriesEarth Sciences Sector, Contribution Series 20160267
PublisherNorthwest Territories Geological Survey
Meeting44th Annual Yellowknife Geoscience Forum; Yellowknife, NT; CA; November 15-17, 2016
File formatpdf
ProvinceNorthwest Territories
Subjectssurficial geology/geomorphology; geochemistry; Phanerozoic; Cenozoic; Quaternary
ProgramSouth Rae Province Bedrock/Surficial geology, GEM2: Geo-mapping for Energy and Minerals
LinksOnline - En ligne (complete volume - volume complet, PDF, 1.72 MB)
AbstractSurficial geology mapping at a 1:100 000 scale and a reconnaissance-scale till sampling survey within the 75A and 75B NTS map sheets were started in 2015 during the first year of the South Rae activity of the Geo-Mapping for Energy Program (GEM-2) of the Geological Survey of Canada. The area lies in the southern part of the Rae Craton and is in large parts covered with glacial sediments. The mapping and geochemical interpretation of the glacial sediments will inform bedrock mapping and mineral exploration programs, and assist with land resource management decisions in this region.
Ground observations were recorded at 157 sites and 94 till samples were collected for compositional analyses including geochemical and heavy minerals. Erosional ice-flow indicators (striations, grooves, roches moutonnées) and streamlined features (crag-and-tail, drumlins) were measured across the two map sheets. Four phases of ice flow have been identified. At a few sites, an old flow of unknown sense (SSE/NNW) and temporal relationship is deduced from poorly defined striations. In contrast, well defined indicators reveal a regional clockwise rotation in ice-flow directions evolving from a southward to a southwestward flow. A late westward flow is recorded only in the north of the map area. The dominant flow is to the southwest. Bedrock exposure varies from 0 to 40%. The sediment cover consists mostly of till (till veneer, till blanket, hummocky till) intersected by NE-SW trending eskers systems and meltwater corridors. These corridors are eroded into the landscape and contain a mixture of glacial and glaciofluvial landforms, and bedrock exposures. The sediment accumulation varies from 1 to 15m and is less abundant in the southern part of the map area.
A study of till composition and ice flow reconstruction is underway to delineate and interpret glacial dispersal patterns. To investigate the U+REE signature in till, a small orientation survey was conducted at the Hoidas Lake REE deposit in Northern Saskatchewan. Samples were taken up-ice and down-ice from known mineralization. Future comparisons will be made to see if the U+REE mineralization signatures in till can be found in the same kind of geological context along the continuation of the Black Bay fault zone in the Northwest Territories. The poster will present preliminary results focusing on the ice flow reconstruction, till composition and the spatial distribution of major and trace elements of the till matrix geochemistry, gold grains and selected indicator minerals.
Summary(Plain Language Summary, not published)
This poster highlights the 2015 till geochemical results from the GEM2 South Rae surficial mapping sub-activity. This data will provide the framework for mineral exploration and baseline assessments to inform land management decisions in this region.