ABSTRACT
The pyrrhotite-rich massive sulphide ores of Dergamish, Ivanovka and Ishkinino in Southern Urals are not typical for VHMS deposits in terms of (1) geodynamic setting corresponding to the Main Urals Fault (MUF) suture zone, (2) association with ultramafic-mafic lithologies, (3) As-Co-Ni-Bi (Au) specialization and the presence of chromite in the massive sulphide ore, (4) mantle origin of metals proved by Re-Os and Pb isotopic data. The deposits are comparable with modern examples of VHMS on ultramafic-mafic seafloor (Mid-Atlantic Ridge, Logatchev field) and sub-seafloor pyrrhotite-rich ores of the Escanaba Trough, Southern Gorda Ridge.
