GEOCHEMICAL FEATURES OF SULFIDES OF THE AKTASH MAGNETITE-POLYMETALLIC DEPOSIT, WESTERN KARAMAZAR, TAJIKISTAN (LA-ICP-MS DATA)

Abstract

The distribution of trace elements in sulfides from various ores of the Aktash magnetitepolymetallic deposit (Tajikistan) is studied using LA-ICP-MS method. Sulfides partly replace banded magnetite ores. Each sulfide type exhibits specific geochemical features. Galena from sulfide-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 sulfide-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 sulfides. The Ag, Se, Bi, Zn, Cd and Ni contents of chalcopyrite from chlorite-pyrrhotite ores are higher than in chalcopyrite from sulfide-magnetite and pyroxene-sphalerite ores. Chalcopyrite from pyroxenesphalerite 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 sulfide-magnetite, chloritepyrrhotite 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