Fluid evolution and mineralization stages of the quartz–hematite ± sulfide veins from the Kuh-e Dom gold prospect, Central Iran
Fazel, Ebrahim Tale; Mehrabi, Behzad; Shabani, Amir Ali Tabbakh
published: Jan 1, 2015
ArtNo. ESP154019201002, Price: 29.00 €
The Kuh-e Dom gold prospect in Central Iran is located in the Urumieh-Dokhtar Magmatic Belt, and is characterized by copper–iron oxide and gold veins, stockworks and breccias hosted by the Eocene Kuh-e Dom intrusion. Mineralization is located within NE–SW to WNW–ESE sinistral faults and likely formed in a subduction-related continental margin. The deposits have a distinct metal composition of Fe, Cu, Bi, Co, and Mo with gold (up to 3 g/t), and the mineral assemblages are quartz, hematite, pyrite, chalcopyrite, emplectite, magnetite, native gold, calcite, barite, chlorite, and tourmaline. Three paragenetic stages of mineralized quartz veins are distinguished in the Kuh-e Dom prospect, including: (i) hematite-bearing quartz veins, (ii) quartz-sulfide stockwork and breccia veins, and (iii) quartz-calcite ± sulfide infilling veins. Sodic (albitization), potassic, and quartz-calcite ± chlorite pervasive alterations are commonly associated with these three mineralization stages. Three types of fluid inclusions have been identified at Kuh-e Dom, including: aqueous two-phase (H2O–NaCl–CaCl2 ± FeCl2), halite-saturated aqueous (H2O–NaCl ± KCl), CO2-bearing (H2O–CO2 ± CH4 and CO2 ± CH4) fluid inclusions. Fluid inclusion data suggest that a hypersaline (∼35 wt.% NaCl equiv.), aqueous magmatic-derived hydrothermal fluid was trapped at about 400 °C and a pressure of nearly 4 kbar, forming early hematite-bearing quartz veins. These early high salinity fluids were progressively diluted, becoming less saline further away from Kuh-e Dom intrusion, suggesting substantial input and fluid mixing of meteoric water during the middle and late stages of mineralization.