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TitleToward a new glacial geology framework supporting geoscience applications in the southwestern Great Slave Lake area
AuthorHagedorn, G W; Ross, M; Paulen, R CORCID logo; Smith, I RORCID logo; Neudorf, C M; Gingerich, T; Lian, O B
Source47th Annual Yellowknife Geoscience Forum, abstracts; by Gervais, S D; Irwin, D; Terlaky, V; Northwest Territories Geological Survey, Yellowknife Geoscience Forum Abstract and Summary Volume 2019, 2019 p. 107-108 Open Access logo Open Access
LinksOnline - En ligne (complete volume - volume complet, PDF, 6.60 MB)
Alt SeriesNatural Resources Canada, Contribution Series 20200046
PublisherNorthwest Territories Geological Survey
Meeting47th Annual Yellowknife Geoscience Forum; Yellowknife, NT; CA; November 19-21, 2019
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories
NTS85C; 85F
AreaGreat Slave Lake; Tathlina Lake; Cameron HIlls; Mackenzie River; Hay River; Kakisa River; Kakisa Lake
Lat/Long WENS-118.0000 -116.0000 62.0000 60.0000
Subjectssurficial geology/geomorphology; stratigraphy; geochronology; Nature and Environment; Science and Technology; glacial history; glaciation; ice flow; deglaciation; modelling; sediments; dunes; beach ridges; glacial deposits; tills; moraines; gravels; glacial features; glacial striations; glacial grooves; glacial landforms; clasts; provenance; fabric analyses; till fabric; pebble lithology; carbonate; till samples; landslide deposits; slumps; Laurentide Ice Sheet; Glacial Lake McConnell; Snake Creek Moraine; Canadian Shield; Canadian Cordillera; ice-flow directions; eolian sediments; Phanerozoic; Cenozoic; Quaternary; Mesozoic; Cretaceous; Paleozoic; Precambrian
ProgramGEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Southern Mackenzie Surficial Mapping
Released2019 11 01
AbstractA better understanding of the Northwest Territories surficial geology is important for addressing topics such as natural resource extraction, permafrost change, infrastructure development, and land use management. The area surrounding southwestern Great Slave Lake (NTS 85C/85F) is one such region requiring greater surficial geological understanding. This region includes several towns and communities, important infrastructure (highways, railroads), is within the discontinuous permafrost zone, and is considered to host a significant mineral resource potential. Our research aims to improve understanding of Laurentide Ice Sheet (LIS) dynamics and evolution of glacial Lake McConnell, as well as the nature and distribution of surficial sediments, regional stratigraphy, and permafrost landforms.
Previous interpretations of ice-flow in the area indicated a generalized westward trajectory. New ice-flow erosional indicators (n=66) provide evidence for an oldest southwest flow (230°), followed by an intermediate westward flow (280°), and a later northwestward flow (305°). Stratigraphic observations and sediment properties (n=160) indicate three distinct till units. The lowest (oldest) till observed is a grey diamicton sourced mainly from local Paleozoic sedimentary rocks. A southwestward ice flow direction is interpreted for this unit based on clast fabrics and is consistent with the oldest erosional ice-flow indicators. The lower till is overlain by a brown diamicton containing a higher proportion of far-travelled Canadian Shield clasts. This brown till contains lodged, elongate boulders with parallel striations on their upper surface and clast fabrics indicating a west to northwestward ice-flow direction, broadly consistent with the interpreted intermediate ice-flow phase. The third till, with a dominant local bedrock provenance, forms a discontinuous unit at surface across the study area. Although no clear stratigraphic constraints were found, the third till appears to be related to the final ice-flow phase. Streamlined landforms, moraines, and other sediment-landform assemblages previously understudied in the region have now been mapped and analyzed in greater detail and further supporting LIS dynamics interpretations and deglacial history.
Minimum deglacial age estimates are better constrained through optical dating of medium-sand deposits in a well-developed raised beach (n=2) and relict aeolian dunes (n=7). Optical dating results indicate distinct shoreline development associated with the retreat of glacial Lake McConnell, and phases of dune development following lake drainage. Interpretation of local LIS dynamics and ice-margin retreat enhances our understanding of the western LIS and will inform practical applications of surficial geology in the southwestern Great Slave Lake area.
Summary(Plain Language Summary, not published)
Student MSc thesis presentation, which is funded by the GEM2 Southern Mackenzie Surficial activity. This poster presentation will be a summary of the surfiicial mapping, glacial stratigraphy and glacial/deglacial chronology.

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