Systematic sulfur stable isotope and fluid inclusion studies on veinlet groups in the Sarcheshmeh porphyry copper deposit: based on new data

Mineralization occurred by intrusion of granodioritic stock of middle Miocene in volcano–sedimenrary rocks in Sarcheshmeh of early Tertiary age. This research is based on samples of new drilled boreholes and benches of 2500m elevation. Based on mineralogy and crosscutting relationships، at least four groups of veinlets pertaining to four stages of mineralization were recognized. Sulfur isotope studies in the Sarcheshmeh porphyry copper deposit were conducted on pyrite، chalcopyrite، molybdenite and anhydrites of four groups of veinlets. The δ34S values in the sulfides and sulfates range from -2. 2 to 1. 27‰ and from 10. 2 to 14. 5 ‰، respectively. The average δ34S value in the sulfides is 1‰ and that for the sulfates is about 13‰. Considering these results، it can be concluded that the sulfides made up of a fluid that its sulfur has a magmatic origin. Also، fluid inclusions of different veinlet groups were studied، showing high temperature، high salinity and the occurrence of boiling in the mineralizing fluids. Moreover، these studies indicate presence of three types of fluids including magmatic، meteoritic and mixture of these two fluids in alteration and mineralizion processes.