N. Taghipour; A. Aftabi; M.R. Ramezani
Abstract
The Miduk porphyry copper deposit is located in 85 Km northwest of Sarcheshmeh porphyry copper deposit, Kerman province. The deposit is hosted by Eocene volcanic rocks of andesite-basalt composition. The porphyry-type mineralization is associated with two calc-alkaline intrusive phases (P1 and Miduk ...
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The Miduk porphyry copper deposit is located in 85 Km northwest of Sarcheshmeh porphyry copper deposit, Kerman province. The deposit is hosted by Eocene volcanic rocks of andesite-basalt composition. The porphyry-type mineralization is associated with two calc-alkaline intrusive phases (P1 and Miduk porphyry) of Miocene age. Five hypogene alteration zones are distinguished in the Miduk deposit, magnetite-rich potassic, potassic, potassic-phyllic, phyllic and propylitic. The main stage of mineralization consists of chalcopyrite, magnetite and anhydrite in potassic alteration zone. The mineralization is mostly associated with Miduk porphyry intrusive phase. Three different types of biotite including magmatic, magmatic affected by hydrothermal fluids and secondary are distinguished at the Miduk deposit. Magmatic type biotites affected by hydrothermal fluids and secondary biotites contain higher XMg values than the magmatic biotites. The XMg are positively correlated with Si, Al, Mg, K, Mg/Ti, but negatively correlated with Al×Ti, Fe, Na, Fe/Ti contents. The variations of Cu, Mo, Au and Ag are controlled by vein - type alteration and mineralization zones. The tonnage of deposit is about 170 Mt with average grade of 0.82 % Cu, 0.007% Mo, 82 ppb Au and 1.8 ppm Ag, respectively. Highest values of Mo and Au occur in leached and oxide, supergene sulfide mineralization, phyllic and potassic-phyllic alteration zones, respectively. Gold displays positive correlation with Cu in magnetite-rich potassic and potassic alteration zones. Based on petrography, mineralogy, alteration halos and patterns of Cu, Au, Ag and Mo, the Miduk porphyry copper deposit is similar to those of continental arc setting porphyry copper deposits.
H. Atapour; A. Aftabi
Abstract
Magmatism in Dehaj- Sarduieh volcanic belt has been occurred in three phases. The first magmatic phase consists of Eocene volcanic rocks (tephrite –phonolite, basalt, trachybasalt, tracyandesite, andesite, dacite, rhyolite and pyroclastic rocks) of Bahraseman, Razak and Hezar complex. With increasing ...
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Magmatism in Dehaj- Sarduieh volcanic belt has been occurred in three phases. The first magmatic phase consists of Eocene volcanic rocks (tephrite –phonolite, basalt, trachybasalt, tracyandesite, andesite, dacite, rhyolite and pyroclastic rocks) of Bahraseman, Razak and Hezar complex. With increasing angle of subduction, the acidic (Bahraseman complex), intermediate (Razak complex) and basic volcanism (Hezar complex) occurred in Dehaj – Sarduieh volcanic belt. After ceasing the volcanism, the Oligo-Miocene granitoid rocks (gabbro-diorite, diorite, monzonite, quartz diorite, granodiorite, quartz monzonite and granite) with calcalkaline, potassic calcalkaline and shoshonitic affinity intruded into the volcanic rocks, forming the first phase of porphyry copper mineralization.The second magmatic pulse includes Neogene volcanic rocks (dacite – rhyodacite- rhyolite ) and plutonic bodies ( diorite – quartz diorite ) of flat subduction- related calcalkaline-adakitic affinity, associated with the second phase of porphyry copper and polymetallic vein mineralization. Polymetallic vein type mineralization occurs in volcanic rocks, but genetically is related to porphyry mineralization and tectonomagmatic characteristics of the belt. The occurrence of ignimbrite strongly indicates a continental arc subduction setting. The high values of incompatible elements such as K, Rb and Ba show that porphyry copper and their host igneous rocks were developed by partial melting of metamorphosed oceanic crust and mantle wedge ( phlogopite eclogite and or phlogopite amphibolite ) in a continental arc setting. The third magmatic phase is characterized by the occurrences of postcollisional lamprophyres and basaltic lavas of potassic and alkaline affinity. The final postmagmatic activity was related to the vast occurrences of Quaternary travertine deposits.
