Pre-emplacement sulfur saturation of Ni-Cu sulfide ore-producing magma at Pechenga, Russia: Evidence from feeder dikes

摘要

1 IntroductionThe 1.98 Ga Pechenga Ni-Cu sulflde deposits are located in the lower part of differentiated, mafic-ultramafic intrusions. The magmatic bodies were emplaced as concordant, sill-like injections into the Pilgujarvi Sedimentary Formation, which is mainly composed of graywackes and shales rich in sulfur and graphite. This, up to 1-km-thick sedimentary unit, which has also been called the Productive Formation, represents the uppermost sedimentary unit of the Pechenga Group and is underlain and overlain by thick piles of submarine, massive and pillowed tholeiitic lavas of the Kolosjoki and Pilguj(a)rvi Volcanic Formations (see Fig. 1).