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TitleMineral systems with IOGC and affiliated deposits: Part 1 - metasomatic footprints of alteration facies
AuthorCorriveau, LORCID logo; Montreuil, J F; Potter, EORCID logo; Ehrig, K; Clark, J M; Mumin, A H; Williams, P J
SourceGeological Association of Canada, Special Paper 52, 2022 p. 113-158
Alt SeriesNatural Resources Canada, Contribution Series 20190065
PublisherGeological Association of Canada
Mediaon-line; digital
RelatedNRCan photo(s) in this publication
File formatpdf
ProvinceCanada; Canada; British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long WENS-180.0000 180.0000 90.0000 -90.0000
Subjectsmineralogy; Science and Technology; Economics and Industry; economic geology; minerals; iron; iron oxides; albite; amphibole; magnetite; mineral deposits; Great Bear Magmatic Zone
Illustrationslocation maps; profiles; photographs; sketch maps
ProgramTargeted Geoscience Initiative (TGI-5) Uranium ore systems
Released2022 07 22
AbstractMetasomatic mineral systems with iron oxide and alkali-calcic hydrothermal alteration chemically and texturally transform significant volumes of the upper crust and produce iron oxide copper-gold (IOCG), iron oxide-apatite (IOA) and affiliated critical metal deposits. By combining the silicate, carbonate and phosphate alteration assemblages with iron oxides, a diagnostic set of alteration 'facies' emerges. A systematic sequence of crosscutting relationships amongst these facies, and spatial zoning relative to depth and heat sources, are illustrated using examples from the Great Bear magmatic zone in Canada, and the Ernest Henry copper-gold and Cu-U-Au-Ag Olympic Dam IOCG deposits in Australia. Facies 1 Na (albite, minor scapolite, residual quartz) is the earliest, most extensive and commonly deepest facies. It forms albitite (composed of >80 modal % albite) corridors up to tens of kilometres long, either at the roots of the systems above intrusions or along major fault zones where the albitite becomes extensively brecciated. The Na facies transitions through Na-Ca (albite-scapolite) and high-temperature Na-Ca-Fe (albite, amphibole, magnetite) assemblages to Facies 2, which is defined by high-temperature Ca-Fe mineral assemblages (amphibole, magnetite, apatite) that replace, vein and cement breccias within albitite zones and least-altered host rocks. The largest footprint of this Ca-Fe facies occurs in carbonate-bearing sedimentary sequences where skarn (clinopyroxene, garnet) may form early, pre to syn albitite, but is progressively replaced by the high-temperature Ca-Fe assemblages. Facies 1 to 2 delineate areas of interest at the regional scale, and also host magnetite skarn and iron oxide-apatite (IOA) deposits. Systems that evolve to Facies 3 high-temperature K-Fe (magnetite-K-feldspar/biotite), Facies 4a K-skarn (clinopyroxene, garnet, K-feldspar), Facies 4b K-felsite (K-feldspar), and Facies 5 lower-temperature K-Fe ± Ca, Mg, H+, CO2, Si and Ba (sericite, K-feldspar, hematite, chlorite, carbonate, epidote) have the capacity to produce extensive breccia zones and significant IOCG deposits. Facies 6 low-temperature K, Si, Al ± Ba, Fe comprises vein systems, phyllic alteration and epithermal lithocaps. The well-constrained relationships among iron oxide and alkali-calcic alteration facies and their distribution within the Australian and Canadian case studies provide a robust framework to interpret fluid pathways and system development globally.
Summary(Plain Language Summary, not published)
This scientific paper is a chapter for the Short course Note 21 volume of the Geological Association of Canada entitled Iron oxide copper-gold (Ag-Bi-Co-U-REE) and affiliated deposits. The paper reviews some of the main outcome of the Targeted Geoscience Initiative Uranium systems project, activity 2.1 ¿¿Metal pathways and traps in polymetallic (U +/- Fe, Cu, Au, REE) metasomatic ore systems¿¿. The paper describes the alteration facies and associated deposit types, and synthesizes ore genesis as the systems build-up. The alteration facies are shown to map the fluid flow paths from sources to deposits. Three main case examples are used: the Olympic Dam and the Ernest-Henry deposits in Australia, archetypes of hematite and magnetite-group IOCG deposits, as well as the Great Bear magmatic zone where depth to surface exposures of ore systems are exceptional and a guide to understand metal pathways to ores including for albitite-hosted uranium deposits such as those of the Central Mineral Belt in Canada, a target of the project.

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