Document Type : Original Research Paper
Authors
1 Faculty of Basic Sciences, Tarbiat Modarres University, Tehran, Iran
2 School of Geology, College of Science, University of Tehran, Tehran, Iran
Abstract
ChahMoosa, Kalate ChahMoosa and GholeKaftaran mining districts are located in the Eastern part of Toroud-ChahShirin magmatic arc. Calc-alkaline subvolcanic bodies' of ChahMoosa porphyry biotite hornblende andesite, GholeKaftaran porphyry biotite hornblende dacite, equivalent to I type granite, intruded Eocene volcanic-pyroclastic sequences. Disseminated-veinlet Cu mineralization in the ChahMoosa mine occurred in subvolcanic porphyry biotite hornblende andesite bodies are associated with phyllic and propylitic alterations. Supergene processes caused extensive alteration of hypogene sulfide minerals such as pyrite, chalcopyrite and bornite to secondary chalcocite, covellite, digenite, malachite and neotocite supergene minerals. Disseminated-veinlet Cu, Zn, Pb mineralization at Kalate ChahMoosa which is limited to a fault zone in porphyry biotite hornblende andesite subvolcanic body. This mineralization is accompanied by phyllic, propylitic, and silicic alterations and includes hypogene minerals such as pyrite, chalcopyrite, sphalerite, bornite, galena, barite and supergene minerals such as chalcocite, covellite, malachite and neotocite supergene minerals. In the abandoned Southern GholehKaftaran Cu mine, Cu bearing veins have occurred in porphyry biotite hornblende dacite body and contain quartz, chalcocite, and malachite. In the abandoned northern GholehKaftaran Pb mine, Pb (Zn, Cu) bearing veins occurred in porphyry biotite hornblende dacite body and they contain galena, sphalerite, pyrite, chalcocite, calcite and barite. Fluid inclusion studies show that homogenization temperature decreases gradually from ChahMoosa toward Kalate ChahMoosa to northern GholehKaftaran. Based on petrography, structures, textures, mineral paragenesis, fluid inclusion and geochemical studies, it can be concluded that mineralization at ChahMoosa-GholeKaftaran district has characteristics of an individual mineralization system. This system is related to evolution of hydrothermal fluid mineralization and their mixing with cold and low salinity meteoric water resulted in disseminated-veinlet Cu mineralization at relatively deep zones, and vein type Cu, Zn, Pb at shallow zones has led to development of elemental and mineralogical zonations.
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