Hydrothermal alteration, lithogeochemical marker units and vectors towards mineralisation at the Svärdsjö Zn-Pb-Cu deposit, Bergslagen, Sweden

The Svärdsjö Zn-Pb-Cu deposit is situated in the heavily mineralised Bergslagen lithotectonic unit of Fennoscandian shield, south-central Sweden. Intense hydrothermal alteration followed by a strong overprint deformation and metamorphism during Svecokarelian orogeny complicate interpretation local geology. Integration whole-rock lithogeochemical petrographic methods has allowed mainly dacitic volcanic host succession effects ore-related to be characterised. Mineralisation hosted 2–15 m thick, commonly skarn-altered dolomitic marble interbeds. Zones strong–intense chlorite-sericite envelop units, recording mass gains Fe Mg, as well Na depletion. Minerals such cordierite, anthophyllite sillimanite formed these rocks regional metamorphism. via sub-seafloor replacement suggested for based on zoning irregular, stratabound, marble-hosted style sulphide lenses. It inferred that mineralisation neutralisation hot, acidic metalliferous fluids. Geochemically lithologically distinct units adjacent zones can serve marker aid further exploration area. Mass change calculations reveal Mg enrichment, depletion exhibit detectable changes extending up 100 from lenses, providing vectors.