Magnetite as a provenance and exploration tool for metamorphosed base-metal sulfide deposits in the Stollberg ore field, Bergslagen, Sweden

Abstract Magnetite is a common mineral in the Paleoproterozoic Stollberg Zn–Pb–Ag plus magnetite ore field (~6.6 Mt of production), which occurs 1.9 Ga metamorphosed felsic and mafic rocks. Mineralisation at consists bodies massive to semi-massive sphalerite–galena pyrrhotite (with subordinate pyrite, chalcopyrite, arsenopyrite magnetite) hosted by metavolcanic rocks skarn. sulfides, skarn, amphibolite altered rhyolitic ash–siltstone that garnet–biotite, quartz–garnet–pyroxene, gedrite–albite, sericitic probably formed from hydrothermal ore-bearing fluids (~250–400°C) replaced limestone ash–siltstone, subsequently recrystallised during metamorphism. The composition these rock types was measured using electron microprobe analysis LA–ICP–MS. Utilisation discrimination plots (Ca+Al+Mn vs . Ti+V, Ni/(Cr+Mn) trace-element variation diagrams (median concentration Mg, Al, Ti, V, Co, Mn, Zn Ga) suggest sulfides more closely resembles skarns found elsewhere rather than previously published compositions volcanogenic sulfide deposits. Although show various have similar patterns, principal component analyses element–element indicate its same type different deposits can be distinguished. This suggests bulk-rock also has strong influence on composition. Principal distinctive compositional signature allows it prospective pathfinder for field.