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TitleThe Otish Basin: basin evolution and formation of the Camie River deposit, Quebec
DownloadDownload (whole publication)
AuthorMilidragovic, D; Lesbros-Piat-Desvial, M; King, J J; Beaudoin, G; Hamilton, M A; Creaser, R A
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. 115-122, https://doi.org/10.4095/295789 (Open Access)
Year2015
PublisherNatural Resources Canada
Documentopen file
Lang.English
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
ProvinceQuebec
NTS22M/13; 22M/14; 22M/15; 22M/16; 23D/01; 23D/02; 23D/03; 23D/04; 32P/16; 33A/01
AreaCamie River
Lat/Long WENS -72.5000 -70.0000 52.2500 51.7500
Subjectssedimentology; radioactive minerals; geochronology; unconformity-type deposit; unconformities; uranium deposits; uranium; mineral deposits; mineral occurrences; mineralization; basin evolution; lithogeochemistry; molybdenite; uraninite; radiometric dating; Otish Basin; Camie River prospect; Precambrian
Illustrationslocation maps; cross-sections; photomicrographs; plots
ProgramUranium Ore Systems, Targeted Geoscience Initiative (TGI-4)
Released2015 03 02 (08:30)
AbstractThe Otish Basin of central Quebec hosts over thirty uranium prospects, including the Camie River prospect that is located near the unconformable contact between the graphite-bearing, metamorphic basement of Archean age and the overlying basinal sedimentary rocks of the Otish Supergroup. The maximum age of the basin, constrained by the age of the unconformably-underlying Mistassini dyke swarm, is 2515 } 3 Ma. Following the deposition of the Otish Supergroup, the basin was intruded by the Otish Gabbros, a suite of olivine-tholeiitic dykes and sills of near-liquid compositions (Group 1) and cumulate rocks (Group 2). Uranium-lead zircon ages from the Otish Gabbros indicate the minimum age of the Otish Basin is ca. 2.17 Ga. The Otish Basin was also intruded by the Matoush dyke, interpreted to be younger than the Otish Gabbros. The least altered samples of the Matoush dyke have mineralogy and trace element systematics, such as highly fractionated REE patterns, similar to lamprophyric rocks and are distinct from the tholeiitic to weakly trace element-enriched Otish Gabbros. This, therefore, indicates that the Otish Basin was affected by at least two igneous events.
The uranium mineralization formed after the peak diagenetic alteration of the Otish Supergroup. During peak diagenetic conditions, early albitic sandstone cement was largely replaced by K-feldspar. The feldspathic cement was subsequently partially replaced by a green muscovite alteration. The increase in Na2O concentrations of the feldpsathiccemented sandstones towards the base of the sedimentary sequence is noteworthy. Uraninite and brannerite are the principal uranium minerals at the Camie River prospect. Molybdenite grains, intergrown with uraninite, yield a Re-Os model age of 1724 } 4. 9 Ma that is indistinguishable from the previously published uraninite ages. The age of mineralization is significantly younger than the age of the Otish Gabbros, indicating that the uranium mineralization postdates sedimentation by ?450 m.y. The overlapping Sm-Nd isotopic ages from Otish Gabbros suggest the main uranium mineralization was locally accompanied by resetting of the Sm-Nd system and LREE mobility in the gabbros. The age of mineralization in the Otish Basin is similar to the age of polymetallic mineralization of the Huronian Supergroup, suggesting the ca. 1.7 Ga hydrothermal activity may have been a regional phenomenon affecting the southern Superior Province.
GEOSCAN ID295789