Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Investigation on Fluid Inclusion in Copper- Molybdenum Porphyry Complex of Sungun, West of Ahar, Eastern Azarbaijan

Document Type : Original Research Paper

Authors
Mahmoud Mehr Partou 1
Mahmoud Torkian 2
1 Geological Survey of Iran, Tehran, Iran
2 Institute of Mineralogy and petrography, Hamburg University, Hamburg, Germany
Abstract
In Sungun area, only within northern part of Sungun Village the magmatic rocks have been affected by advanced alteration and ore mineralization. The host rocks consist of granite and granodiorite which are characterized by calc- alkaline, I- type granite of a continental arc geotectonic setting. According to geological data from peripheral rock units, emplacement of the intrusion is post- Eocene in age, which is simultaneous with the Pyrenean orogeny. Pronounced pervasive alteration produced potassic, phyllitic, argillic and propylitic alteration zones of immense extent. Secondary biotite and K-feldspar are typical alteration products in the inner zone of intrusive rocks. Hypogene mineralization consists of disseminated and vein type mineralization. Disseminated minerals mostly occur in inner parts and are identified by chalcopyrite in potassic zone and pyrite in propylitic zone. Chalcopyrite vein type mineralization occur in intermediate zone and mostly in stockwork. Results of fluid inclusion study show that the mineralization was controlled by some physico-chemical parameters such as temperature- pressure, pH, and by influx of meteoric waters. The first stage of mineralization mainly took place at temperatures between 350 to 450°C, and in some cases even at C. The presence of more than 540 C, and a second stage of mineralization occurred at 250 to 350 daughter crystals of halite and sylvite in fluid inclusions of high salinity suggest metal transport in hydrothermal fluids enriched in chlorine complexes, Some outcrops of variable thickness surround porphyry copper deposit. Copper ore skarn type mostly occurs in contact between productive stock and Cretaceous limestone. Pyrite and minor chalcopyrite were deposited in the first stage of mineralization whereas the second stage is characterized by chalcopyrite, galena, sphalerite and magnetite. Apart from stockwork with irregular joints and fractures, ore emplacement was controlled by two conjugated joints and in some cases by faults which were responsible for conductivity of hydrothermal fluids. Mineralized dykes with relative concentric distribution contain only pyrite. They surround porphyry deposit and suggest later mineralization in studied area. Two specific patterns of fractures and joints were established in Sungun deposit. The first type is thought to have occurred simultaneously with intrusion emplacement and especially caused concentric, radial fractures and dykes and the second type is harmonized by common fracturing pattern in Sungun area and correlates with the main lineament of the Pyrenean orogeny.
Subjects
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Scientific Quarterly Journal of Geosciences
Volume 3, Issue 10
Winter 1994, Vol. 3, No. 10
Winter 1994
Pages 2-27