Determining the origin and evolution process of ore-bearing fluids based on the investigation of fluid inclusions in Majid Abad region (northeast of Ahar - northwest of Iran)
Subject Areas :Hanie Babai 1 , Seyed Ghafor Alavi 2 , vartan Simmonds 3
1 - University of Tabriz
2 -
3 - Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
Keywords: Epithermal, Porphyry, Fluid inclusion, Mineralization, Majid Abad.,
Abstract :
The Majid Abad area is located in the northwest of Iran, East Azarbaijan province and 32 km northeast of Ahar. In terms of structural-tectonic classification of Iran, this region is located in the Alborz-Azarbaidjan zone and is part of the NW end of Urumieh-Dokhtar magmatic arc. The rock units of the region include Eocene igneous and pyroclastic rocks with andesite, trachy-andesite to trachy-basalt composition and Oligocene intrusive bodies of monzodiorite and gabbro composition. Mineralization is in the form of disseminations and veins-veinlets, which occurred in two separate stages, hypogene and supergene. Hypogene ore minerals include pyrite and chalcopyrite, which are accompanied by supergene chalcocite, covellite, digenite, hematite, limonite and malachite. In the investigation of fluid inclusions, 5 types of fluid inclusion were observed, including mono-phase liquid, mono-phase vapor, two-phase liquid-rich, two-phase vapor-rich and multiphase, occurring within ore-braing quartz veins. Based on the microthermometry results, the homogenization temperature and salinity of the examined fluid inclusions are 142 to 567 °C and 4 to 53 wt.% NaCl equivalent, respectively. The effective ligands in the transportation of metals are chloride and sulfide, and the occurrence of boiling, cooling and dilution with atmospheric fluids is the main cause of the deposition of metallic elements and the mineralization in Majid Abad area. On this basis, mineralization in Majid Abad area took place in an epithermal condition and probably related to a porphyry system.