New data on the mineralogy of the gold-sulfide ore type of the Karalveem deposit, Chukotka

Abstract

In this paper, we present the results of a mineralogical study of the ores of the Karalveem deposit in the northeast of Russia (Central and Ruslovy areas). Gold mineralization is characterized by two types of ores: gold-quartz-arsenopyrite (quartz veins with native gold and sulfide mineralization) and gold-sulfide (metasomatites) in gabbrodolerite. In most samples, both types of ores are combined, making these complex ores are of particular interest. The main ore mineral is arsenopyrite; secondary and accessory minerals include pyrite, rutile, ilmenite, galena, chalcopyrite, monazite, sphalerite, and native gold. Native gold in quartz-sulfide and gold-sulfide ore types is present in a free form as microveinlets, micron-size segregations in the host rock, or as microinclusions in sulfides. Both ore types are characterized by the similar chemical composition of ore minerals: the fineness of gold in the gold-sulfide type is 870–900 ‰, in veins – 840–910 ‰. The trace element composition of pyrite and arsenopyrite from metasomatites and quartz veins is also alike. Based on this, it was concluded that the productivity of gold-sulfide and gold-quartz-arsenopyrite ores was formed by a single impulse.