Mineralogy, geochemistry and fluid inclusions in Ghorban polymetal deposit, SE of Damghan, Central Iran

Ghorban polymetallic deposit is located in the Torud-Chahshirin Range, at the northeast end of Cheshmeh Hafez mining district in the northern margin of the Central Iran geotectonic zone. The bed rocks of the area consist mainly of volcanic to sub-volcanic of Middle to Upper Miocene in age, such as basalt, andesite-basalt, andesite, trachy-andesite, tuff, agglomerate, and breccia tuff. These rocks have been pervasively altered by hydrothermal fluids. Alterations include propylitic, sericitization, chloritization, argillic and silicification. Mineralization occurred in both hypogene and supergene zones of the area. Geochemical studies show that Cu has a very low correlation with Zn and Pb and a positive correlation with Ag. Au also has the highest correlation with Ni. Fluid inclusions have been done in a quartz samples as well as one calcite sample which are associated with ore minerals. Fluid inclusions at room temperature are liquid-rich bi-phasic type. Most of them are made up of liquid fluid only and a few of them are made up of liquid fluid with vapor bubble. Homogenization temperature and salinity in the samples are between 112-254 ℃ and 0.88- 18.22 wt% NaCl equivalents. The homogenization temperature and fluid salinity data shows that mineralization has taken place due to injection of several phases of high saline fluid and mixing with low saline fluid and was diluted during the cooling. Mineralogical, geochemical and fluid inclusions data show that the Ghorban pollymetals deposit is epithermal deposits.