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TitleTill provenance across the terminus of the Dubawnt Lake ice stream, central Nunavut
AuthorMcMartin, I
SourceGeological Survey of Canada, Current Research (Online) 2017-1, 2017, 16 pages, (Open Access)
PublisherNatural Resources Canada
Mediaon-line; digital
File formatpdf; docx
ProvinceNunavut; Northwest Territories
NTS66C/09; 66C/10; 66C/11; 66C/12; 66C/13; 66C/14; 66C/15; 66C/16; 66D/09; 66D/10; 66D/11; 66D/12; 66D/13; 66D/14; 66D/15; 66D/16; 66E; 66F; 66K; 66L; 66M; 66N; 76A/09; 76A/10; 76A/11; 76A/12; 76A/13; 76A/14; 76A/15; 76A/16; 76B/09; 76B/10; 76B/11; 76B/12; 76B/13; 76B/14; 76B/15; 76B/16; 76C/09; 76C/10; 76C/11; 76C/14; 76C/15; 76C/16; 76F/01; 76F/02; 76F/03; 76F/06; 76F/07; 76F/08; 76F/09; 76F/10; 76F/11; 76F/14; 76F/15; 76F/16; 76G; 76H; 76I; 76J; 76K/01; 76K/02; 76K/03; 76K/06; 76K/07; 76K/08; 76K/09; 76K/10; 76K/11; 76K/14; 76K/15; 76K/16; 76N/01; 76N/02; 76N/03; 76N/06; 76N/07; 76N/08; 76N/09; 76N/10; 76N/11; 76N/14; 76N/15; 76N/16; 76O; 76P
AreaQueen Maud Gulf; Bathurst Inlet; Ellice River; Back River; Garry Lake; Queen Maud Gulf Migratory Bird Sanctuary; Thelon Game Sanctuary; Canadian Shield
Lat/Long WENS-109.5000 -100.0000 68.0000 64.5000
Subjectssurficial geology/geomorphology; geochemistry; stratigraphy; glaciation; ice flow; sediment transport; ice margins; glacial deposits; glacial landforms; glacial features; tills; moraines; glaciofluvial deposits; eskers; glacial striations; frost boils; clasts; textures; textural analyses; till geochemistry; trace element analyses; major element analyses; provenance; source rocks; bedrock geology; lithology; sedimentary rocks; sandstones; conglomerates; igneous rocks; intrusive rocks; leucogranites; monzo-granites; granodiorites; tonalites; diorites; magnetite; diatexites; volcanic rocks; rhyolites; metavolcanic rocks; metasedimentary rocks; metamorphic rocks; gneisses; migmatites; silica; quartz; strontium; clay minerals; clays; zinc; till stratigraphy; facies; till samples; sediment colour patterns; mineral exploration; paleogeography; shoreline changes; Dubawnt Lake Ice Stream; MacAlpine Moraine System; Dubawnt Basin; Thelon Basin; Rae Province; Thelon Tectonic Zone; Rae Craton; Slave Craton; Thelon Formation; Pitz Formation; Dubawnt Supergroup; Queen Maud Block; Duggan Lake Domain; ice front; till composition; Phanerozoic; Cenozoic; Quaternary; Precambrian
Illustrationslocation maps; sketch maps; photographs; geochemical profiles; geochemical plots
ProgramRae Province, Chantrey-Thelon, GEM2: Geo-mapping for Energy and Minerals
Released2017 03 21; 2017 04 13
AbstractThe composition of glacial sediments across the Dubawnt Lake ice stream in central mainland Nunavut was examined to assess the potential influence of fast ice flow on sediment transport. Major changes in clast content, texture, and geochemical composition are observed in till collected over and beyond the ice-stream footprint. These changes coincide with an ice-front position at the southern segment of the MacAlpine moraine system. The till composition over the ice stream reflects a distal provenance, rich in undeformed Dubawnt Supergroup sandstone debris from the Thelon basin, relatively clay-rich, SiO2-rich, and depleted in most trace and major elements (except SiO2). Although giving an indication of the long glacial transport distance of exotic quartz sandstone from the Thelon Basin (~80 km), the SiO2 content in the matrix (<0.063 mm) is not entirely appropriate to reflect the Thelon Basin component in the till because of the abundance of quartz-rich rocks in the local crystalline basement. The ratio of total versus partial concentrations of Sr in till is a better suited proxy in the Thelon tectonic zone region; Sr ratios below ~10 characterize till composition within the Dubawnt Lake ice stream. Beyond the ice stream, till composition reflects a more local provenance, derived from the underlying Thelon tectonic zone rocks, and Sr ratios increase up to ~24. Furthermore, atypical clay contents in till, related to changes in till facies or stratigraphy rather than a change in provenance, can have a significant influence on till composition and may complicate the interpretation of till geochemistry. The work has implications for mineral exploration in the Rae geological province of the Canadian Shield.
Summary(Plain Language Summary, not published)
This publication provides a preliminary discussion on the composition of glacial sediments across former glacial landscapes in central mainland Nunavut and examines the potential influence of fast ice flows on sediment transport. The work was completed as part of the surficial geology component of the GEM-2 Rae Project Thelon-Chantrey Activity and has implications for surface mineral exploration methods in the Rae geological Province of the Canadian Shield. The findings will support informed decision making for resource exploration and development, and for land use management.