Mehdi Koohsari, Mohammad Boomeri, Sasan Bagheri,
Volume 32, Issue 3 (10-2024)
Abstract
The Sefidabeh and Heydar Abad antimony mines are located in the northwest of Zahedan in the Sistan suture zone. The rock units in the area are Cretaceous ophiolitic complex, Eocene flysch sequence, Oligocene conglomerate and Oligocene intermediate igneous rocks. The antimony mineralization occurs as quartz-stibnite veins in the Oligocene conglomerate along the faulted zone. The hypogene sulfide minerals are stibnite with minor amounts of pyrite. The supergene minerals are hematite, goethite, limonite, stibiconite and senarmontite. The main alteration types are silicic, argillic and carbonate that occurred around the veins and are mainly characterized with quartz, chalcedony, clay and calcite. The common ore textures are open space filling and brecciated. Coliform and comb structure and bladed and acicular stibnite crystals are observed in microscopic and mesoscopic scales as well. The vein type hypogene sulfides are formed by hydrothermal fluids in fractures and faults The result of micro-thermometry of fluid inclusion in quartz show that the homogenization temperatures the ranges from 130 to 420 ºC and salinities ranges from 4 to 5.68 wt. % NaCl eq. that are mainly in range of those of epithermal ore deposits. The mineral assemblage, alteration types and ore texture show that antimony mineralization in Sefidabeh and Heydar Abad mines is of low-sulfidation epithermal type, which are controlled by strike-slip faults.
