The distribution of platinum-group elements (PGE) and stable isotope (O, H, S) geochemistry of Gunes-Sogucak Ni-Cu-sulfide mineralization, in Divrigi-Sivas, East-Central Turkey

Abstract

The Gunes-Sogucak Ni-Cu-Sulfide mineralization from Divrigi district in Sivas province, central-east Turkey is genetically related to Upper Cretaceous ultramafic rocks, and observed as disseminated and vein type. Disseminated mineralization scattered trough ultramafic rocks. However, vein type mineralization is seen in the fracture zones of ultramafic rocks. Both disseminated and vein type Ni-Cu-Sulfide mineralizations show depletion of Ni- and Cu and also show enrichment of platinum-group elements (PGE), Au and Ag with respect to primitive mantle. Average metal concentrations of the Cu-Ni-sulfide mineralization are; Ni: 106, Cu: 263 in ppm; Ru: 293, Pt: 26, Pd: 126, Au: 87, Ag: 316 in ppb. The depletions in Ni and Cu and enrichments in PGEs, An and Ag may have resulted from chemistry of hydrothermal fluids during its evolution. delta(34) S-SigmaS values range from 7.9 to 14.6 parts per thousand, with most values at the higher end of this range. Given the range of sulfur isotope values for our data, it is evident that there must have been a component of sedimentary sulfate present in the hydrothermal fluids. delta D values of waters trapped in quartz crystals range from -69 to -90 parts per thousand and delta(18)O values of quartz range from 11 to 15. Based on delta(18)O and delta D data, combined with the geologic setting of the deposits, we propose that the ore fluids were dominated by magmatic waters. S isotopes indicate that the intrusion assimilated a portion of its sulfur from sedimentary sulfates during ascent.