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TitleIce-flow history and regional stratigraphy of the northwestern Laurentide Ice Sheet, evidence from the Great Slave Lake area
AuthorHagedorn, G; Ross, MORCID logo; Paulen, RORCID logo; Smith, RORCID logo
SourceGAC®-MAC 2021, London, Canada: Exploring Geosciences Through Time and Space/GAC®-MAC 2021, London, Canada : Explorer les géosciences à travers le temps et l'espace; Geological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Abstracts Volume vol. 44, 2021 p. 122 Open Access logo Open Access
LinksOnline - En ligne (complete volume - volume complet, PDF, 2.45 MB)
Alt SeriesNatural Resources Canada, Contribution Series 20210032
PublisherGeological Association of Canada
MeetingGAC-MAC 2021: Geological Association of Canada-Mineralogical Association of Canada Joint Annual Meeting 2021; London, ON; CA; November 1-5, 2021
Mediadigital; on-line
File formatpdf
ProvinceNorthwest Territories
NTS85C; 85F
AreaGreat Slave Lake
Lat/Long WENS-118.0000 -116.0000 62.0000 60.0000
Subjectssurficial geology/geomorphology; stratigraphy; mineralogy; sedimentology; economic geology; Nature and Environment; Science and Technology; glacial history; glaciation; ice flow; mineral exploration; mineral potential; exploration methods; glacial deposits; tills; clasts; boulders; glacial landforms; pebble lithology; oxides; provenance; fabric analyses; Laurentide Ice Sheet; Canadian Shield; ice-flow directions; Phanerozoic; Cenozoic; Quaternary; Paleozoic; Precambrian
ProgramGEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Southern Mackenzie Surficial Mapping
Released2021 11 01
AbstractReconstructing the evolution of past ice sheets and understanding their net effect on landscapes and surficial sediments provide important insights into long-term glacial processes, as well as useful knowledge for mineral exploration in glaciated terrains. The evolution of the northwestern Laurentide Ice Sheet is poorly understood due to a limited number of field-based studies. Our research addresses this knowledge gap around the southwestern shore of Great Slave Lake. Our goal is to reconstruct the ice flow chronology of this region and trace the dominant provenance of subglacial tills to improve our understanding of past ice-sheet configuration and subglacial sedimentary processes. Relative ice-flow chronology is established using glacial landforms, outcrop-scale ice-flow indicators, as well as till stratigraphic and provenance analyses. Outcrop-scale indicators show a shift in ice flow direction from an oldest southwestern (230°) flow, to a western (250°) flow, to a final northwestern (305°) flow. Lodged boulders and till clast fabrics from till stratigraphic sections across the study area are broadly consistent with the clockwise ice flow shift. Indicators of northeast provenance include Canadian Shield clasts and certain major oxides (e.g. Cr2O3, Fe2O3) that are considered enriched in northeast bedrock sources relative to local bedrock. At least one till unit is associated with the southwest ice-flow phase based on landforms, till clast macro-fabrics, and a discernible northeast provenance (Canadian Shield) signature. Younger tills were deposited during the clockwise ice flow shift. These tills are located in lower elevation areas of the study area and their composition has an increased Paleozoic (local bedrock) signature, but also includes input from Paleozoic strata to the east. The integrated ice flow records from this study, along with previous studies from the Pine Point mining district, show compelling evidence for major shifts in ice sheet configuration and flow dynamics, as well as related subglacial conditions (e.g. changes in subglacial sediment entrainment) during the last glaciation.
Summary(Plain Language Summary, not published)
This is a presentation from a GEM-funded MSc research project, on the distribution and geochemistry of the tills that occur at the surface in the southwestern part of the NWT. This will assist in understanding the various influences that past glacial flows have impacted the landscape, to assist future mineral exploration in the region.

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