New Insights into the Petrography and Mineralogy of the Malenkiy Site (Pay-Khoy, Nenets Autonomous District)

The rock composition and ore mineralization of the Malenkiy site located within the Khengur gabbro-dolerite complex of the Pay-Khoy were examined. Petrogeochemical analysis revealed two varieties of the studied rocks: fine-crystalline quartz and medium- and coarse-crystalline quartz containing metagabbro-dolerite. The Y, Zr, and Nb contents suggest that metagabbro-dolerites formed in an intraplate setting from enriched mantle sources during the melting of garnet peridotite, with a small contribution from the melt source of ancient continental crust. Two types of ore mineralization were distinguished: nest- and veinlet-disseminated sphalerite-chalcopyrite-pyrrhotite (type I) and veinlet-disseminated cobaltite-pentlandite-chalcopyrite-pyrrhotite (type II). The most efficient ore mineralization was type II, which is characterized by the presence of both high-temperature cobalt- and nickel-bearing sulfide minerals, as well as low-temperature tellurides of palladium (kotulskite) and silver (hessite).