Intrusion-related mineralization in the Palaeo-proterozoic Jörn Granitoid Complex, northern Sweden

Immediately north of the Skellefte mining district, northern Sweden, the early orogenicsynvolcanic Jörn granitoid complex hosts several mineral deposits. The Jörn granitoid batholith intruded into a continental margin arc or island arc volcanic succession during the early Proterozoic, and comprises a composite, I-type, calc-alkaline batholith, ranging from granite to gabbro in composition. Several mineral deposits occur in the heterogeneous margin of the complex, i.e. the Tallberg porphyry Cu-Au-Mo, the Älgträsk Au and the Älgliden Ni-Cu-Au deposits in the south and the Näsberg Fe±PGE and Granberg porphyry Cu mineralization in the north. The known deposits indicate that the intrusion is fertile for further exploration activities and that Palaeoproterozioc synvolcanic intrusions close to VMS districts should be studied more closely to further develop genetic models which can be used to reconstruct the ore forming environments and tectonic evolution. This knowledge might be used as guidelines when exploring for new districts with economic potential in Palaeoproterozoic terrains.Godkänd; 2009; 20091116 (thebej