Moissanite Nanoparticles in Disseminated Mineralization of the Dukat Ore District, Northeastern Russia

摘要

Different polytype modifications of silicon carbide are widespread among diverse igneous rocks. It is believed that they are related to the earliest high-temperature stage of melt crystallization, when minerals formed under strongly reducing high-pressure conditions at temperatures over 1800℃. In the diamondifer-ous rocks of alkaline ultramafic complexes, this accessory mineral (typical polymorphic modification 6H) is normally represented by crystals 1-7 μm in size. We found moissanite in the form of unusual crystals and intergrowths of nanoparticles among the disseminated mineralization typical of silicified rhyolites of the Dukat ore district. The Dukat ore district is confined to the sublongitu-dinal riftogenic Balygychan-Sugoi Trough, which frames the Okhotsk-Chukot volcanic belt on the north . The studied areas of disseminated base metal mineralization are located south of the ore field including the large Dukat gold-silver deposit. Ore minerals of the deposit are mainly represented by zinc, lead, and copper sulfides with subordinate tin sulfides. The most valuable components are native Ag and acanthite. The ore field includes several linear zones of carbonaceous metasomatites (tuffisites).