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TitleMineralogy of a fertile fluid conduit related to unconformity-type uranium deposits in the Athabasca Basin, Saskatchewan
DownloadDownload (whole publication)
AuthorAdlakha, E E; Hattori, K; Zaluski, G; Kotzer, T G; Davis, W J; Potter, E G
SourceTargeted Geoscience Initiative 4: unconformity-related uranium systems; by Potter, E G (ed.); Wright, D M (ed.); Geological Survey of Canada, Open File 7791, 2015 p. 74-82, (Open Access)
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
RelatedThis publication is contained in Potter, E G; Wright, D M; (2015). Targeted Geoscience Initiative 4: unconformity-related uranium systems, Geological Survey of Canada, Open File 7791
File formatpdf
ProvinceAlberta; Saskatchewan
NTS64E; 64L; 64M; 74E; 74F; 74G; 74H; 74I; 74J; 74K; 74L; 74M; 74N; 74O; 74P
Lat/Long WENS-112.0000 -102.0000 60.0000 57.0000
Subjectseconomic geology; radioactive minerals; mineralogy; unconformity-type deposit; unconformities; uranium deposits; uranium; mineral deposits; mineral occurrences; mineralization; hydrothermal alteration; hydrothermal deposits; structural features; faults; formation fluids; Athabasca Basin
Illustrationscross-sections; location maps; tables; photographs; photomicrographs; plots
ProgramTargeted Geoscience Initiative (TGI-4), Uranium Ore Systems
Released2015 03 02 (08:30)
This report documents the occurrence and chemical variation of hydrothermal alteration minerals along the P2 fault, the structural host for the world-class McArthur River uranium deposit, in order to identify the mineralogical footprint of ore-forming fluids, define exploration criteria for fertile basement structures associated with this deposit type and infer the nature of the fluids. An assemblage of florencite (LREE-rich aluminum phosphate-sulphate; APS) and magnesio- foitite (alkali deficient Mg tourmaline) with sudoite and illite formed in the basement rocks along the P2 fault and is distinct relative to the alteration assemblages that formed in the basement rocks outside the fault. This assemblage occurs along the entire P2 fault, regardless of its proximity to the McArthur River uranium deposit and is interpreted to be the mineralogical footprint of ore-forming fluids. It may be useful when targeting fertile basement faults during exploration. Compositional zoning in APS minerals indicate that earlier fluids were SO4 2--rich and became P and LREErich through interactions with the basement rocks. The chemical composition of florencite and magnesio-foitite indicates that mineralizing fluids contained low Na and were enriched in REE, especially in the ore zone. High d11B values in magnesio-foitite are interpreted as being sourced from B dissolution by fluids from evaporitic rocks. The similar chemistry and occurrence of these minerals along the entire P2 fault, regardless of proximity to ore, indicate that the P2 fault was a conduit for mineralizing fluids and that the precipitation of uranium was selective to the location of the McArthur River deposit.