Origin of a barite-sulfide ore deposit in the Mykonos intrusion, cyclades: Trace element, isotopic, fluid inclusion and raman spectroscopy evidence

摘要

The polymetallic Mykonos vein system in the Cyclades, Greece, consists of 15 tension-gashes filled with barite, quartz, pyrite, sphalerite, chalcopyrite and galena in ca. 13.5 Ma, I-type, Mykonos monzogranite. Zones of silica and chlorite-muscovite alteration are associated with the veins and overprint pervasive silicification, phyllic and argillic alteration that affected large parts of the monzogranite. The mineralization cements breccias and consists of an early barite-silica-pyrite-sphalerite-chalcopyrite assemblage followed by later argentiferous galena. A combination of fluid inclusion and stable isotope data suggests that the barite and associated mineralization were deposited from fluids containing 2 to 17 wt.% NaCl equivalent, at temperatures of similar to 225 degrees to 370 degrees C, under a hydrostatic pressure of <= 100 bars. The mineralizing fluids boiled and were saturated in H2S and SO2.