Remobilization and element redistribution in volcanic-hosted massive sulphide deposits of the Skellefte district, northern Sweden: constraining the role of metamorphic fluid processes

• Applicant: Professor Dr. Thomas Wagner
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2004 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5435418

Several of the metamorphosed volcanic-hosted massive sulphide deposits in the Skellefte metallogenic district, northern Sweden, display crosscutting vein-type mineralization of various compositions including most notably Au ± Bi-Te-Se, AuCu, Au-Zn ± Pb, and Cu types. The genetic links between these vein ores and the massive orebodies are still under debate, with metamorphic remobilization and shear zone-controlled introduction being the end-member concepts. The results of preliminary studies of sulphosalt-Au veins from the Boliden deposit indicate the significance of metamorphic remobilization for the formation of these assemblages. It is proposed to expand the investigation to include different vein and ore types from four representative deposits across the district that have been subjected to different degrees of deformation and metamorphism (Kristineberg, Storliden, Renström, Boliden). The study will address the following objectives: (1) Mineralogicalgeochemical characterization of the different styles of veintype mineralization in the VMS deposits, including detailed structural and textural studies, electron-microprobe analysis, stable isotopes (S, O and H) and fluid inclusion analysis; (2) reconstruction of the physico-chemical conditions and computerassisted thermodynamic modelling of the mineralizing processes; (3) development of a comprehensive genetic model that describes both the processes that formed vein-type mineralization and the factors controlling their spatial distribution.

• DFG Programme: Research Grants
• International Connection: Switzerland