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TitreThe Role of Paragneiss Assimilation in the Origin of the Voisey's Bay Ni-Cu Sulfide Deposit, Labrador: Multiple S and Fe Isotope Evidence
AuteurHiebert, R S; Bekker, A; Wing, B A; Rouxel, O
SourceEconomic geology and the bulletin of the Society of Economic Geologists vol. 108, (2013), 2013 p. 1459-1469,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20140557
Mediapapier; numérique; en ligne
SNRC14C/04; 14C/05; 14D/08; 14D/01
Lat/Long OENS -62.0833 -61.5000 56.3333 56.1667
Sujetsrapports des isotopes de soufre; études des isotopes stables; gisements minéraux; paragneiss; gîtes sulfureux; gîtes magmatiques; magmatisme; differentiation magmatique; roches magmatiques; plutons; géologie économique; géochimie; pétrologie ignée et métamorphique; minéraux métalliques
Illustrationsgeologic sketch map; equations; graphs; tables
ProgrammeÉtude des gîtes magmatiques de Ni-Cu-EPG, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
Isotopic and geochemical studies conducted on the Voisey's Bay deposit, Labrador, Canada, suggest crustal contamination of the primary magma as a trigger for sulfur saturation and formation of the deposit. The use of multiple S isotopes has allowed for the identification of a bacterial sulfate reduction biosignature in the Tasiuyak gneiss in the footwall to the Voisey's Bay deposit. This putative biosignature is preserved in the deposit even at high silicate magma/sulfide melt ratios (R-factor) and links the S present in the Voisey's Bay deposit to the Tasiuyak gneiss. Iron isotopes in the Voisey's Bay deposit have been reset to magmatic values at R-factors > ˜100, but S isotope data can be used to model higher R-factors. A contamination model results in calculated R-factors of 433 ± 177. The multiple S isotope data are a new proxy to directly link S from the deposit to crustal S sources even in deposits with high R-factors where the equilibration with large amounts of silicate magma can make interpreting a link between the deposit and the sulfur source difficult