Alteration in the area of the Kristineberg VHMS deposit, Skellefte district, Sweden.

The Skellefte district in north-central Sweden is one of the most important mining districts in northern Europe. It contains over 85 pyritic Zn-Cu-Au-Ag massive sulphide deposits of which 21 deposits have been mined since 1924 and 4 are still in operation by Boliden Mineral AB. The most productive deposit, the Kristineberg mine, has been operated by Boliden since 1940 with a current annual production of 670,000 t of polymetallic ore containing 3.0 wt.-% Zn, 0.7 wt.-% Cu, 0.4 wt.-% Pb, 1.9 g/t Au and 47 g/t Ag. Alteration of the volcanic rocks around the Kristineberg deposit is very intense. The main aim of this study has been to describe the alteration intensity and to define alteration trends around the Kristineberg deposit. The success of this approach provides a new exploration tool for future exploration in the Skellefte District where alteration renders the recognition of primary volcanic facies difficult.