eology, mineralization and fluid inclusion studies of the Lakhshak gold deposit, southwest Sistan suture zone

Lakhshk deposit is located 28 km northwest of Zahedan and southwestern of Sistan suture zone. The main outcrops in the study area are Eocene schists consisting of calc-schist and quartz schist. These rocks metamorphosed under greenschist facies grade and were intruded by Oligocene rhyolitic and dacitic dikes and granitoid. The gold-antimony mineralization is structurally controlled by a NE–SW fault zone and shear zone, and hydrothermal alterations were mainly occurred in the contact zones of granitoid and calc-schist units. The high-grade gold mineralization (3.5 g/t) is spatially related to the intense sulfidation and silicification hydrothermal alteration zones in the inner parts of the zone as well as ductile-brittle (microfractures, fine veins/veinlets) deformation. The ore mineralogy is simple and includes pyrite, arsenical pyrite, stibnite, chalcopyrite, arsenopyrite, pyrrhotite, sphalerite, gold, electrum, goethite, and stibiconite. The study of fluid inclusions on gold ores quartz shows the homogenization temperature in quartz-sulfide veins/veinlets with mineralization between 200 to 330 °C with a salinity of 8 to 13 wt.% NaCl equiv., which is compatible with the mixing and dilution process. Based on the results of geology, mineralogy, and fluid inclusion studies, gold mineralization in Lakhshak gold deposit is of orogenic type.