Nickel-Ore Formation in Island-Arc Magmatism, Kamchatka

Mineralogical, chemical, and isotopic data have been obtained for samples from 11 volcanoes and 4 kortlandite intrusives on Kamchatka.Similarities and differences in ore-bearing and barren intrusives are discussed. Differences in sulphide mineralization and sulphur isotope compositions of intrusives are explained in terms of the "auto-sulphurization" hypothesis which involves the redox conditions of the host rocks. possible role for carbon in nickle sulphide ore formation is also considered.