Geochemical features of sulfides of the Aktash magnetite-polymetallic deposit, Western Karamazar, Tajikistan (LA-ICP-MS data)

Abstract

The distribution of trace elements in sulfdes from various ores of the Aktash magnetite-polymetallic deposit (Tajikistan) is studied using LA-ICP-MS method. Sulfdes partly replace banded magnetite ores. Each sulfde type exhibits specifc geochemical features. Galena from sulfde-magnetite ores contains the higher amount of elements of «high-temperature» association (Bi, Ag, Cu) than galena from pyroxene-sphalerite ores, which, in addition to Ag and Bi, also contains higher amount of elements of «medium-temperature» association (Se, Te, and Sb). Sphalerite from sulfde-magnetite and chlorite-pyrrhotite ores contains higher Fe, Cd and Mn amount than sphalerite from pyroxene-sphalerite ores, which is characterized by elevated Co and As contents. Pyrite is depleted in trace elements except for As, the content of which is maximum compared to other sulfdes. The Ag, Se, Bi, Zn, Cd and Ni contents of chalcopyrite from chlorite-pyrrhotite ores are higher than in chalcopyrite from sulfde-magnetite and pyroxene-sphalerite ores. Chalcopyrite from pyroxene-sphalerite ores is characterized by elevated Pb, As, Ge, Te and Sb contents. Relatively high Co, Ni and Se contents are determined in pyrrhotite. In addition to Fe, Cu, Zn, Pb and Au, which form minerals in all types of ores, we suggest by-product extraction of following elements from complex sulfde-magnetite, chlorite-pyrrhotite and pyroxene-sphalerite ores (the Bi, Ag, Se and Te contents of galena and Cd content of sphalerite are shown in brackets): Bi (19520–24650 ppm), Ag (7907–9650 ppm), Se (397–606 ppm) and Te (276– 436 ppm) from galena concentrate and Cd (8525–27670 ppm) from sphalerite concentrate.