ABSTRACT
The Mississippi Valley-type lead-zinc deposits of Mežica are hosted by Middle/Upper Triassic Wetterstein platform carbonates in the Northern Karavanke, Slovenia. The main ore sulfides have negative δ34S values within a range of more than 28 ‰ which support sulfide origin by bacterial sulfate reduction. Variations of δ34S of galena and coarse-grained sphalerite at orefield scale are generally larger than the differences observed in single hand specimens. The results best support local δ34S variations of the sulfide source, and that sulfur from disconformable orebodies originated from leaching of earlier sulfide species of conformable ore.
