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TitreGeology, mineralization and alteration of the turbidite-hosted Mustang Au showing, Lower Eastmain greenstone belt, Superior Province, Quebec
TéléchargerTéléchargement (publication entière)
AuteurBeauchamp, A -M; Dubé, B; Malo, M; McNicoll, V J; Brisson, T; Archer, P; Lavoie, J; Chartrand, F
SourceTargeted Geoscience Initiative 4: Contributions to the understanding of Precambrian lode gold deposits and implications for exploration; par Dubé, B (éd.); Mercier-Langevin, P (éd.); Commission géologique du Canada, Dossier public 7852, 2015 p. 227-243, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
Mediaen ligne; numérique
Référence reliéeCette publication est contenue dans Dubé, B; Mercier-Langevin, P; (2015). Targeted Geoscience Initiative 4: Contributions to the understanding of Precambrian lode gold deposits and implications for exploration, Commission géologique du Canada, Dossier public 7852
SNRC33C/01; 33C/02; 33C/07; 33C/08
Lat/Long OENS -76.5833 -76.4167 52.3333 52.0000
SujetsArchéen; gîtes minéralogiques; gisements minéraux; minéralisation; or; cuivre; métaux de base; gisements de métaux de base; déformation; altération; altération hydrothermale; roches ignées; métamorphisme; interprétations tectoniques; cadre tectonique; turbidites; caractéristiques structurales; datations au uranium-plomb; géologie économique; géologie structurale; géochronologie; Précambrien
Illustrationslocation maps; photographs; stereonets; histograms; photomicrographs; plots
Bibliothèque de Ressources naturelles Canada - Ottawa (Sciences de la Terre)
ProgrammeÉtude des gîtes d'or, Initiative géoscientifique ciblée (IGC-4)
Diffusé2015 06 11
Résumé(disponible en anglais seulement)
The Mustang gold showing is located on the Wabamisk property owned by Exploration Osisko - Baie James. The Mustang Vein (N240/80°) is located near the contact between the La Grande and Opinaca subprovinces in the Superior Province, 65 km southwest of the Éléonore gold mine. The gold zone is exposed on surface and can be traced through drillholes over a strike length of 570 m and to a depth of 225 m. The vein and its mineralized envelope range from a few centimetres to six metres in width. Gold values obtained for the vein reach 111.17 g Au/t over 2.6 m in channel sample and 22.65 g Au/t over 2.25 m in drillhole. More than 75 gold showings (Au >500 ppb) were discovered over a 10 by 10 km area around the Mustang Vein. The Mustang Vein is a quartz (±carbonate) laminated vein hosted in turbiditic metasedimentary rocks (greenschist facies) located near the top of an Archaean stratigraphic sequence of the Eastmain Belt. The preliminary results of U-Pb dating on detrital zircons of the metasedimentary rocks hosting the Mustang Vein indicate a maximum deposition age of 2709 ±4 Ma. The sedimentary sequence has undergone at least three deformation phases, including an initial phase of north-northwest-oriented folding with F1 folds refolded by east-northeast-oriented F2 folds. The S2 foliation is oriented east-northeast with a steep dip and an axial plane with P2 folds. The D3 deformation phase is characterized by a moderate-dip, southwest-oriented crenulation cleavage. The Mustang Vein is subparallel to the bedding and folded into S shapes by the F2 folds. It is interpreted as syn-D2 regional deformation, along a F2 fold limb. The vein and the altered walls (potassic alteration and carbonatization) contain 1-10% arsenopyrite, 5-10% pyrrhotite, with traces of pyrite, chalcopyrite, galena, and sphalerite. Locally, gold grains in the veins and altered host rock are disseminated and aligned on the main S2 foliation planes.
The geological context and mineralization, alteration, and deformation styles at the Mustang showing are analogous to syn-deformation deposits hosted in turbidite sequences (e.g. Meguma in Nova Scotia and Central Victoria in Australia). Like the Roberto Gold Deposit (Éléonore Mine), the Mustang gold showing illustrates the potential for folded Archaean metasedimentary assemblages of the La Grande Subprovince proximal to the tectono-metamorphic boundary of the Opinaca Subprovince to host major gold deposits in the James Bay Region.