Investigation of cu vein of the Shurk and associated gossan zone (North West of Birjand) based on alteration, mineralization, geochemistry and fluid inclusion

The Shurk area located in the west of Birjand city is a part of the Lut Block volcanic-plutonic belt. Preliminary prospecting in the area using ASTER satellite data processing in method of spectral angle mapper enhanced propylitic, argillic alteration and iron oxides. The area comprises outcrops of Eocene volcanics, which was intruded by subvolcanic intrusions with gabbro to diorite composition. The vein mineralization was formed in two stages, including: 1) quartz-pyrite-chalcocite-chalcopyrite-bornite-fahlore-sphalerite that are associated with argillic-silicified alteration and 2) quartz-chalcocite-sphalerite accompained with silicified-carbonate alteration. Primary fluid inclusions of quartz in paragnesis with minealization in the first and second stages of vein mineralization, have an average of homogenization temperatures 267°C and 215 °C respectively. Based on freezing studies, the average of final ice melting temperature (Tfmice) equals to 19.4 and 11.1 wt.% NaCl respectively. Mixing, dilution with meteoric water and boiling have been effective during the evolution of hydrothermal fluids and the formation of ore-bearing veins. Based on evidences such as structural control of mineralization, the type of alteration, simple mineralogy of ore and thermometric data, the Shurk deposit is similar to those of epithermal deposits. The presence of numerous Cu veins on a large scale indicates significant economic potential of area.