Forecasting criteria for sulphide pge-copper-nickel deposits of the noril’sk province

Abstract

Research subject. World-class sulphide platinum-group-element (PGE)-Cu-Ni deposits occur within the Noril’sk-Talnakh region of northern Siberia, Russia. The significance of these deposits presents opportunities to determine the most effective approaches for the search of similar deposits using commercial PGE-Cu-Ni deposit examples. Materials and methods. Petrological and geochemical analysis of the ultramafic-mafic intrusions of the Noril’sk province ranks them into three types in terms of sulphide mineralization style and economic significance: 1) economic intrusions containing unique and large sulphide PGE-Cu-Ni deposits (Oktyabr’sk, Talnakh and Noril’sk-1); 2) subeconomic intrusions that contain small-to medi-um-sized Cu-Ni sulphide deposits, and medium-sized to large PGE deposits (Chernogorsk, Zub-Marksheider, Vologochan, etc.); 3) uneconomic intrusions that contain low-grade disseminated Cu-Ni ores with ≈0.2 wt % of Cu and Ni, and low Cr and PGE (Nizhny Talnakh, Zelyonaya Griva, etc.). Results and conclusions. Principal sources used in exploration for rich sulphide PGE-Cu-Ni ores include structural, magmatic, stratigraphic-lithological, geochemical, mineralogical, metamorphic and some others. Based on an analysis of isotope-geochemical data, new indicators for locating sulphide PGE-Cu-Ni mineralization are suggested. A restricted range of S-isotope values, and a negative trend for coupled S-Cu isotope compositions can be employed as useful guides to assess the economic potential of a PGE-Cu-Ni sulphide deposit. It is proposed that the Chernogorsk ultramafic-mafic intrusion of the Noril’sk province is the most promising target in a search for rich PGE-Cu-Ni ores. It is suggested that the previously known mineralogical-geochemical and novel isotope-geochemical characteristics of sulphide and silicate minerals are important indicators in assessing the potential ore content of ultrama-fic-mafic intrusions of the Noril’sk province.