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TitleGlacial stratigraphy and till micromorphology at Pine Point, southern Northwest Territories, Canada
 
AuthorSapera, J; Menzies, J; Paulen, RORCID logo
SourceINQUA 2019, Dublin, Ireland: 20th Congress of the International Union for Quaternary Research (INQUA); P-1863, 2019 p. 1 Open Access logo Open Access
LinksOnline - En ligne
Image
Year2019
Alt SeriesNatural Resources Canada, Contribution Series 20180394
PublisherInternational Union for Quaternary Research
MeetingINQUA 2019, Dublin, Ireland: 20th Congress of the International Union for Quaternary Research (INQUA); Dublin; IE; July 25-31, 2019
DocumentWeb site
Lang.English
Mediaon-line; digital
File formathtml; pdf
ProvinceNorthwest Territories
NTS85B/09; 85B/10; 85B/11; 85B/14; 85B/15; 85B/16
AreaPine Point; Great Slave Lake
Lat/Long WENS 14.0000 15.5000 61.0000 60.5000
Subjectssurficial geology/geomorphology; stratigraphy; sedimentology; geochemistry; mineralogy; economic geology; Nature and Environment; Science and Technology; glacial deposits; tills; till stratigraphy; depositional environment; depositional history; deformation; ice margins; clasts; fabric analyses; till geochemistry; mineral exploration; exploration methods; mines; open pits; Laurentide Ice Sheet
ProgramGEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Southern Mackenzie Surficial Mapping
Released2019 07 01
AbstractThe Pine Point Mississippi Valley-type (MVT) Pb-Zn mining district extends 50 km along an east-west trend south of Great Slave Lake, Northwest Territories, in northern Canada. The district contains 50 open pits that expose glacial sediments, in some cases more than 20 m thick, providing a unique opportunity for glacial stratigraphic analyses. A detailed stratigraphic study is being undertaken on a thick (>20 m) basal till sequence at open pit M-52 in the north-central part of the district. The goal of the research is to augment the existing knowledge of the regional Quaternary stratigraphy and to investigate the mechanics of till deposition/emplacement throughout the continuous till sequence to better understand the glacial dynamics for the western margin of the Laurentide Ice Sheet. Additionally, the glacial stratigraphy at pit M-52 will be correlated with the previous research conducted within the mining district, regionally with Quaternary sections exposed along the Mackenzie River to the west, and extensionally with seismic shothole and diamond drill hole stratigraphic databases. Till samples were collected for macro- and micro-sedimentological studies.
Macrosedimentology studies incorporate glacial stratigraphy, sedimentology, clast fabrics, geomorphology, and laboratory analyses for matrix geochemistry and indicator minerals. The walls of pit M-52 expose two visibly distinct tills, a grey till exposed at the base of the section and an upper brown till. When a complete vertical section was cleared and examined, the contact between the two tills was indiscernible and suspected to be gradational over several metres. The upper brown till could reflect surface oxidation of the lower grey till. However, based on previous research conducted in the region, it is unlikely that there is only a single till exposed in the pit walls. The suspected gradational contact is likely a product of extensive glacial inheritance and mixing as glacial dynamics shifted during till accretion. Clast fabrics were measured in the section and revealed that the grey till close to the bedrock surface reflects SW ice flow, the middle of the section in the gradational zone reflects NW flow, and the brown till near the top displays evidence of NW ice flow.
Detailed glacial microsedimentological data analyses for 38 samples, collected from the two till units, will be used to determine the stress conditions and rheological environments during till emplacement/ deposition. The use of micromorphology in this study is as a primary tool for the analysis of these subglacial sediments, providing far greater detail on the depositional and deformation histories recorded by these sediments than previously obtained from macroscale studies.
Summary(Plain Language Summary, not published)
This is GEM-2 funded student MSc research being presented at an international conference, in a special session on glacial micromorphology.
GEOSCAN ID313618

 
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