Geochemical and fluid inclusion studies of Au and Cu bearing veins in the Hureh area, West Iran
Abstract
The Hureh Au-Cu veins are located north of Shahrekord, in the central part of the Sanandaj-Sirjan Zone (SaSZ). Mineralized country rocks consist of Mesozoic volcanic, sedimentary and low-grade metamorphic rocks. Main vein minerals are quartz, adularia, carbonates, pyrite, chalcopyrite, chalcocite, covellite, malachite, azurite, hematite, magnetite and goethite. Mineralization occurs as veins, vein swarms, stockwork, and as disseminated and breccia type with quartz, adularia, illite, calcite, hematite, chlorite and sericite as gangue minerals. The analyzed vein samples show up to 1343 ppm Au and > 10000 ppm Cu. The vein minerals reflect the near neutral-pH and reduced composition of the ore fluid. Micro-thermometric analyses show that the salinity of the ore-bearing fluid was between 6.74 and 10.74 wt% NaCl equiv. Fluid inclusion microthermometry indicates mineralization temperatures between 180° and 290 °C. Minimum pressure at the time of fluid entrapment is estimated at about 50 to 100 bars, equivalent to hydrostatic depths of 110 to 150 m. The main factors that gave rise to the Hureh mineralization are an island arc tectonic setting, presence of fractures and faults, and permeabil-ity of the country rocks. The Hureh mineralization can be classified as a low sulfidation epithermal system. © 2022 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany.