Genetic Model and Origin of Ore-Forming Fluids in the Hureh Cu Au Deposit Based on Mineralogical, Fluid Inclusion, and Stable S–O Isotope Data

Zamanian, Masoud; Jafari Rad, Alireza; Lotfi, Mohammad; Nezafati, Nima

doi:10.22071/gsj.2026.591047.2261

Genetic Model and Origin of Ore-Forming Fluids in the Hureh Cu Au Deposit Based on Mineralogical, Fluid Inclusion, and Stable S–O Isotope Data

Articles in Press

Document Type : Original Research Paper

Authors

Masoud Zamanian ¹

Alireza Jafari Rad ¹

Mohammad Lotfi ¹

Nima Nezafati ²

¹ Department of Earth Sciences, SR.C., Islamic Azad University, Tehran, Iran

² Deutsches Bergbau-Museum Bochum, Germany

10.22071/gsj.2026.591047.2261

Abstract

The Hureh Cu–Au district is located in the central part of the Sanandaj–Sirjan Zone, 40 km northeast of Shahrekord, Chaharmahal and Bakhtiari Province. Long‑term orogeny with multi‑stage metamorphism has extensively altered and reworked the rock structures. Host rocks include shale, radiolarian mudstone, slate, phyllite, metamorphosed sandstone and metavolcanic rocks, recrystallized limestones, and microdioritic to granodioritic dykes. Mineralization is associated with NW‑trending faults (dip 68°–85° toward SW) and is characterized by hypogene minerals including magnetite, pyrite, chalcopyrite, and bornite, as well as supergene enrichment comprising native copper, chalcocite, covellite, and cuprite. Fluid inclusion studies in mineralized quartz veins indicate NaCl–CO₂–H₂O ore‑forming fluids with salinities of 6–9 wt% NaCl and homogenization temperatures below 200°C, consistent with orogenic gold systems. Stable isotope measurements yielded δ³⁴S values of 3.36–5.02‰ for pyrite and δ¹⁸O values of 21.30–21.41‰ for quartz. Calculated values for the ore‑forming fluid were δ¹⁸O = 3.1–4.4‰ and δ³⁴S = 1.4–3.1‰. These results indicate that the mineralizing fluids were predominantly metamorphic in origin, derived from prograde metamorphism of organic‑rich sedimentary protoliths. In addition, subduction of the Neotethyan oceanic crust beneath the Iranian continental crust likely contributed to supplying part of the fluid or materials involved in the mineralization process.

Keywords

Fluid inclusions

Ore‑forming fluids

Orogenic gold

Hureh Cu–Au deposit

Subjects