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TitleCharacterization and dispersal of indicator minerals associated with the Pine Point Mississippi Valley-type (MVT) district, Northwest Territories, Canada
AuthorOviatt, N M; Gleeson, S A; Paulen, R C; McClenaghan, M B; Paradis, S
SourceCanadian Journal of Earth Sciences vol. 52, no. 9, 2015 p. 776-794, (Open Access)
Alt SeriesEarth Sciences Sector, Contribution Series 20140401
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
RelatedThis publication is related to Hall, G E M; Hall, G E M; McClenaghan, M B; McClenaghan, M B; (2013). Field portable XRF in exploration and mining, New frontiers for exploration in glaciated terrain, Geological Survey of Canada, Open File 7374
File formatpdf
ProvinceNorthwest Territories
NTS85A; 85B
AreaGreat Slave Lake; Pine Point
Lat/Long WENS-115.0000 -114.0000 61.0000 60.0000
Subjectseconomic geology; surficial geology/geomorphology; geochemistry; mineral deposits; lead; zinc; mineral exploration; exploration methods; drift prospecting; glacial deposits; tills; grain size analyses; sphalerite; galena; pyrite; sulphur; geochemical analyses; Pine Point Lead Zinc Deposit; mississippi valley type deposits; indicator minerals; Phanerozoic; Cenozoic; Quaternary; Precambrian
ProgramHudson/Ungava Project Management, GEM2: Geo-mapping for Energy and Minerals
AbstractA glacial dispersal study was conducted around a subcropping Pb–Zn deposit (O28) in the Pine Point Mississippi Valley-type (MVT) district, Northwest Territories, Canada, with the intent of characterizing and documenting the indicator minerals and their dispersal from a known orebody. Mapping of striations adjacent to deposit O28, and throughout the Pine Point district, along with observed glacial stratigraphy, indicate that there are three phases of ice flow that have affected the Pine Point district. Sphalerite, galena, and pyrite were identified in mineralized bedrock samples at deposit O28, and sphalerite and galena were recovered from the sand fraction of till samples up to 500 m from the mineralized subcrop. The majority of sphalerite and galena grains recovered from till samples down-ice of deposit O28 were 0.25–0.5 mm in size. Size and morphology of sphalerite grains in till demonstrate relative proximity to their bedrock source, with the largest and more angular grains being closer to the ore zone (<50 m) whereas smaller and more rounded grains occur further down-ice (~250 m). The paragenesis, textures, major-element concentrations, and S and Pb isotopic compositions of bedrock samples from deposit O28 and from newly drilled core from four other deposits were characterized. Concentrations of Zn in bedrock sphalerite grains range from 43.95 to 67.48 wt.%, concentrations of S range from 32.03 to 34.01 wt.%, and concentrations of Fe range from 0.02 to 16.94 wt.%. The Fe concentration in bedrock sphalerite decreases from east to west across the district. Concentrations of S in galena grains in bedrock range from 12.50 to 14.00 wt.% and have a bimodal distribution. Generally, the geochemistry of sphalerite grains recovered from till were statistically similar to bedrock grains recovered from deposits O28 and L65. Major-element concentrations were statistically the same between the sphalerite grains recovered from till and the honey-brown and cleiophane varieties in the bedrock samples. Galena grains recovered from till samples were similar to the cubic and fracture-fill varieties of grains recovered from bedrock in the R190 and M67 deposits. Sulphur isotopic values for sphalerite grains from bedrock range from 20.6‰ to 24.2‰, while those from till samples range from -5.3‰ to 24.4‰. Lead isotopic ratios for galena grains from bedrock and till samples had very little variation, which is a characteristic of the Pine Point district. The S and Pb isotopic studies as well as major-element geochemistry suggest that indicator minerals derived from Pine Point-type mineralization can be distinguished from those sourced from other types of carbonate-hosted mineralized systems (e.g., Cordilleran zinc-lead deposits) and that the methods here can be used as exploration tools for identifying MVT deposit provenance or potential. The results of this study present criteria and highlights additional methods for exploration of MVT deposits in glaciated terrain.
Summary(Plain Language Summary, not published)
This journal paper is a summary of the indicator mineral glacial dispersal research conducted at the Pine Point Mississippi-Valley type Pb-Zn district, Northwest Territories. This research was part of the GEM (2008-2013) Tri-Territorial Indicator Mineral Project, and this paper represents much of the M.Sc. thesis research conducted by the senior author. This research informs the exploration industry on the application of base metal indicator minerals for exploration in glacial terrain of northern Canada, in order to increase exploration effectiveness.