Economic sulfides occur in metasedimentary rocks in a Proterozoic supracrustal formation surrounded by granitoid massives at Saxberget in the province of Bergslagen, south central Sweden. The occurrences of high grade metamorphic minerals indicate that the Saxberget Formation has been subjected to temperatures above 600°C and pressures exceeding 300 MPa. Present temperature measurements, combined with analyses of ore elements, indicate that the present mineralization could be the surviving remnant of a formerly overlapping larger system of ZnS-PbS-precipitations which have since been lost to erosion. During deformation, the Saxberget Formation developed chevron folding, during which the thin sulfide mineralized layer flowed from the straight limb into the sharp hinge.