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TitleFormation of albitite-hosted uranium within IOCG systems: the Southern Breccia, Great Bear magmatic zone, Northwest Territories, Canada
AuthorMontreuil, J -F; Corriveau, LORCID logo; Potter, E GORCID logo
SourceMineralium Deposita 49, 2014.,
LinksSupplementary material / matériel supplémentaire -1 (.xlsx 804 KB)
LinksSupplementary material / matériel supplémentaire -2 (.xlsx 18 KB)
Alt SeriesEarth Sciences Sector, Contribution Series 20110238
PublisherSpringer Nature
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthwest Territories
AreaLou Lake
Lat/Long WENS-116.8000 -116.7278 63.5556 63.5333
Subjectsmetallic minerals; geochemistry; mineral deposits; uranium deposits; albite; alteration; mineralization; albitization; exploration guidelines; hydrothermal alteration; deformation; potash feldspars; tourmaline; Great Bear magmatic zone; Wopmay Orogen; Southern Breccia; NICO deposit; Precambrian
Illustrationsbox plots; geological sketch maps
ProgramGEM: Geo-mapping for Energy and Minerals Iron-oxide Copper-gold (IOCG) / Multiple Metals - Great Bear Lake (NWT)
Released2014 07 08
AbstractUranium and polymetallic U mineralization hosted within brecciated albitites occurs one kilometer south of the magnetite-rich Au--Co--Bi--Cu NICO deposit in the southern Great Bear magmatic zone (GBMZ), Canada. Concentrations up to 1 wt% U are distributed throughout a 3 by 0.5 km albitization corridor defined as the Southern Breccia zone. Two distinct U mineralization events are observed. Primary uraninite precipitated with or without pyrite--chalcopyrite ± molybdenite within magnetite--ilmenite--biotite--K-feldspar-altered breccias during high-temperature potassic--iron alteration. Subsequently, pitchblende precipitated in earthy hematite--specular hematite--chlorite veins associated with a low-temperature iron--magnesium alteration. The uraninite-bearing mineralization postdates sodic (albite) and more localized high-temperature potassic--iron (biotite--magnetite ± K-feldspar) alteration yet predates potassic (K-feldspar), boron (tourmaline) and potassic--iron--magnesium (hematite ± K-feldspar ± chlorite) alteration. The Southern Breccia zone shares attributes of the Valhalla (Australia) and Lagoa Real (Brazil) albitite-hosted U deposits but contains greater iron oxide contents and lower contents of riebeckite and carbonates. Potassium, Ni, and Th are also enriched whereas Zr and Sr are depleted with respect to the aforementioned albitite-hosted U deposits. Field relationships, geochemical signatures and available U--Pb dates on pre-, syn- and post-mineralization intrusions place the development of the Southern Breccia and the NICO deposit as part of a single iron oxide alkali-altered (IOAA) system. In addition, this case example illustrates that albitite-hosted U deposits can form in albitization zones that predate base and precious metal ore zones in a single IOAA system and become traps for U and multiple metals once the tectonic regime favors fluid mixing and oxidation-reduction reactions.

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