Document Type : Original Research Paper
Authors
1 M.Sc., Mineralogy Lab., Iran Mineral Processing Research Center (IMPRC), Tehran, Iran
2 Associate Professor, Islamic Azad University, Tehran North Branch; Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
3 3Associate Professor, Islamic Azad University, Tehran North Branch; Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
4 Ph.D. Student, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
5 Ph.D., Faculty of Earth Sciences, Kharazmi University, Tehran, Iran
Abstract
The mineralized veins at Nikuyeh are located south of the Tarom-Hashtjin metallogenic province in Alborz-Azarbayejan belt (West Alborz). Rhyodacite and andesite/andesitic basalt volcanic rocks are hosting the vein mineralization in the Nikuyeh ore district. Hydrothermal alteration in host rocks consists of propylitic, sericitic, argillic and silicic. Mineralization in Nikuyeh occurs in both hypogene and supergene forms in three stages: early stage includes pyrite, magnetite, chalcopyrite and bornite; middle stage includes galena, sphalerite and minor chalcopyrite, and late stage includes malachite, cerussite, covellite, hematite and goethite. Fluid inclusion studies on quartz and calcite show homogenization temperatures ranging between 185°C to 312°C and 133°C to 251°C, respectively. The salinities range from 0.5 to 5.5 wt% NaCl eq. in quartz and 0.3 to 5.4 wt% NaCl eq. in calcite. Boiling is supported by the occurrence of coexisting vapor-rich and liquid-rich inclusions, hydrothermal breccias, microcrystalline quartz, chalcedony and bladed calcite. Boiling and cooling are considered as the main mechanisms for ore deposition. Ore mineralogy, alteration assemblages and fluid inclusion data allow mineralization in Nikuyeh ore district to be classified as low sulfidation epithermal type.
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