Temperature dependences of sulfur isotope fractionation factors between sulfides (experiment and implications)

An elemental synthesis of pairs of molybdenum sulfide with lead, zinc, antimony and tungsten sulfide as well as of the galenite-herzenbergite pair was carried out under controlled conditions. The temperature dependences were established for heavy sulfur isotope refractionation between the above sulfides and applied to the Losen ore field, Eastern Rhodopes, Bulgaria. The sulfur isotope composition of sulfides from the productive galenite-sphalerite-chalcopyrite mineral assemblage from the Losen deposit was determined. The temperatures of deposition of major metallic sulfides at the metal deposition stage were estimated. A decrease in the sulfur isotope content from +7 to +3 per mille is related to the temperature drop from 350 to 250 degC in the course of evolution of the hydrothermal system. (author). 4 tabs., 13 refs