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TitleThe Voisey's Bay deposit, Labrador, Canada
AuthorNaldrett, A J; Li, C
SourceMineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods; by Goodfellow, W D (ed.); Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5, 2007 p. 387-407
Year2007
Alt SeriesNatural Resources Canada, Contribution Series 20170068
PublisherGeological Association of Canada, Mineral Deposits Division (St. John's, NL, Canada)
Documentserial
Lang.English
Mediapaper; DVD; digital
RelatedThis publication is contained in Goodfellow, W D; (2007). Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods, Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5
File formatpdf
ProvinceNewfoundland and Labrador
NTS14D/08
AreaVoisey's Bay; Nain
Lat/Long WENS -62.5000 -62.0000 56.5000 56.2500
Subjectseconomic geology; metallic minerals; geochemistry; mineral deposits; mineral occurrences; mineral potential; mineralization; exploration; mineral exploration; nickel; copper; sulphides; sulphide deposits; igneous rocks; intrusive rocks; gabbros; breccias; troctolites; isotope geochemistry; ore genesis; mineral deposits genesis
Illustrationssketch maps; photographs; stratigraphic sections; graphs; models
ProgramConsolidating Canada's Geoscience Knowledge
ProgramTargeted Geoscience Initiative (TGI-3), 2005-2010
AbstractThe Voisey’s Bay Ni-Cu deposit currently comprises 78x106 tonnes of proven, probable, indicated, and inferred mineralization grading 2.20 wt.% Ni, 1.70 wt.% Cu, and 0.134.% Co. It was discovered in October 1994, and stimulated an intense program of exploration in 1995, 1996, and 1997 for Ni deposits in neighbouring parts of Labrador. The deposit is associated with two 1.334 Ga troctolite intrusive chambers, the upper Eastern Deeps and lower Reid Brook chambers, connected by a 10 to 100 m wide dyke. The igneous rocks are part of the Nain Plutonic Suite that consists of anorthositic, granitic, troctolitic, and ferrodioritic intrusions emplaced between 2.334 and 1.29 Ga. The mineralization is composed of massive, semimassive, and disseminated pyrrhotite, pentlandite, and chalcopyrite located within
the dyke (particularly where it widens) in gneiss adjacent to the dyke and along the line of entry of the dyke to the upper of the two chambers. The sulphides are associated with a magmatic breccia (referred to as feeder breccia or basal breccia) and with troctolite that is commonly close to this breccia. The trace element and Pb and Nd isotope geochemistry of the troctolites indicate that they have interacted with crustal rocks, both at depth and close to the level of the intrusions. Sulphur and oxygen isotopes suggest some interaction with the local gneisses; the radiogenic nature of the Os demands such interaction. The Ni and Fo content of the olivine indicates that early injections of troctolite experienced significant chalcophile depletion, but that later influxes of magma experienced less depletion, and upgraded early sulphides in chalcophile metals. The existence and richness of the Voisey’s Bay deposit is attributed to its occurrence within a plumbing system that has served to focus repeated pulses of magma. Other prospects discovered during the
exploration rush in Labrador are thought to be of lesser size or grade for one or more of the following reasons: (i) the magma with which they interacted was more fractionated than the Voisey’s Bay troctolites, and thus contained less Ni; (ii) there was a lack of adjacent sulphur-rich country rocks with which the magma could interact; and/or (iii) the magma involved was not focussed within a well defined conduit.
GEOSCAN ID224189