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TitleMicrosedimentological evidence of vertical fluctuations in subglacial stress from the northwest sector of the Laurentide Ice Sheet, Northwest Territories, Canada
AuthorRice, J MORCID logo; Menzies, J; Paulen, R CORCID logo; McClenaghan, M BORCID logo
SourceCanadian Journal of Earth Sciences vol. 56, no. 4, 2018 p. 363-379,
Alt SeriesEarth Sciences Sector, Contribution Series 20160177
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html
ProvinceNorthwest Territories; Alberta; British Columbia
NTS75D; 75E; 75L; 84M; 84N; 84O; 84P; 85A; 85B; 85C; 85D; 85E; 85F; 85G; 85H; 85I; 85J
AreaGreat Slave Lake; Pine Point; Hay River; Yellowknife
Lat/Long WENS-119.0000 -110.0000 63.0000 59.0000
Subjectssurficial geology/geomorphology; sedimentology; stratigraphy; geophysics; glacial history; glaciation; ice flow; depositional history; depositional environment; sediment dispersal; depositional models; deformation; glacial deposits; tills; stress analyses; shear stress; lineations; thin section microscopy; pebble lithology; fabric analyses; lithostratigraphy; sedimentary structures; rheology; remote sensing; satellite imagery; Pine Point Mining District; Western Canada Sedimentary Basin; Canadian Shield; Laurentide Ice Sheet; ice-flow directions; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; geoscientific sketch maps; satellite images; photographs; photomicrographs; tables; schematic representations; ternary diagrams; equal-area stereonet projections; charts; stratigraphic sections; rose diagrams; profiles
ProgramGEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Southern Mackenzie Surficial Mapping
Released2018 11 14
AbstractThe past-producing Pine Point lead-zinc mining district, Northwest Territories, Canada, provides a unique opportunity to study the role of glacial dynamics in a thick, continuous till succession that has not been influenced by the underlying bedrock topography. Parts of the Pine Point mining district are covered by >20 m of subglacial Quaternary sediments (till) associated with the former Laurentide Ice Sheet. Till facies exposed in unreclaimed open-pit K-62 have been classified into four separate units. Micro- and macrosedimentological analyses were undertaken to identify the change in subglacial stress during sediment deposition and across till unit boundaries. An analysis of high- and low-angle microshears (lineations) in thin sections produced from these till units indicate that there is a noticeable decrease in the abundance of low-angle shear features immediately below till unit boundaries. The deformation of low-angle shears in the underlying tills was likely caused by remobilization of the overlying till unit. This remobilization is consistent with aggradation-constant entrainment decay mechanisms for subglacial till emplacement and accretion and subglacial dispersion models.
Summary(Plain Language Summary, not published)
This paper is the product of the GSC's GEM1 RAP Bursary funded MSc thesis by Jessey Rice. It is a summary of the detailed sedimentological work that was undertaken with the regional stratigraphy of the western sector of the Laurentide Ice Sheet. Examination of a till sequence, by thin section micromorphology, will provide a better understanding of depositional mechanics under a temperate ice sheet. This paper will benefit academia in a better understanding of the subglacial processes that impacted western and northern Canada.

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