Geology and Re‐Os Geochronology of Mineralization of the Miduk Porphyry Copper Deposit, Iran

Abstract

The Miduk porphyry copper deposit is located in Kerman province, 85 km northwest of the Sar Cheshmeh porphyry copper deposit, Iran. The deposit is hosted by Eocene volcanic rocks of andesitic -basaltic composition. The porphyry-type mineralization is associated with two Miocene calc-alkaline intrusive phases (P1 and P2, respectively). Five hypogene alteration zones are distinguished at the Miduk deposit, including magnetite-rich potassic, potassic, potassic -phyllic, phyllic and propylitic. Mineralization occurs as stockwork, dissemination and nine generations (magnetite, quartz -magnetite, barren quartz, quartz-magnetite-chalcopyrite-anhydrite, chalcopyrite -anhydrite, quartz-chalcopyrite-anhydrite-pyrite, quartz-molybdenite-anhydrite ± chalcopyrite ± magnetite, pyrite, and quartz-pyrite-anhydrite ± sericite) of veinlets and veins. Early stages of mineralization consist of magnetite rich veins in the deepest part of the deposit and the main stage of mineralization contains chalcopyrite, magnetite and anhydrite in the potassic zone. The high intensity of mineralization is associated with P2 porphyry (Miduk porphyry). Based on petrography, mineralogy, alteration halos and geochemistry, the Miduk porphyry copper deposit is similar to those of continental arc setting porphyry copper deposits. The Re-Os molybdenite dates provide the timing of sulfi de mineralization at 12.23 ± 0.07 Ma, coincident with U/Pb zircon ages of the P2 porphyry. This evidence indicates a direct genetic relationship between the Miduk porphyry stock and molybdenite mineralization. The Re-Os age of the Miduk deposit marks the main stage of magmatism and porphyry copper formation in the Central Iranian volcano-plutonic belt. Keywords : alteration , central Iranian volcano-plutonic copper belt , Miduk porphyry copper deposit , mineralization , Re-Os geochronology . ( Shahabpour, 2000 ).The Miduk porphyry copper deposit is located in the Shahr-Babak area in Kerman province, Iran. This deposit is located 85 km NW of the Sar Cheshmeh porphyry copper deposit ( Fig. 1 ). Preliminary mineral exploration in this area was carried out in 1967 -1970 by Parjam and Metallgesellschaft ( Hassanzadeh, 1993 ). So far, more than 50 diamond drill holes with a maximum depth of 1013 m have proved the existence of the sizeable and potential porphyry copper mineralization at the Miduk deposit. The orebody contains 170 million tons of ore, with an average grade of 0.86% Cu, 0.007% Mo, 82 ppb Au and 1.8 ppm Ag. Supergene enrichment blankets average approximately 50 m thickness and comprise the primary source of Cu ore.To further understand the regional and local geologic relationships and timing of mineralization, this contribution presents aspects of petrography, alteration, mineralization, vein classifi cation and Re-Os isotope age of molybdenite in the Miduk deposit. Regional geology of Miduk areaThe oldest units in the area ( Fig. 2 ) are CenomanianTuronian calcareous fl ysch ( Saric et al. , 1971 ) that are unconformably overlain by Paleocene Kerman cong...

The Miduk porphyry Cu deposit, Kerman, Iran: A geochemical analysis of the potassic zone including halogen element systematics related to Cu mineralization processes

“…Igneous activity in this zone started in the Eocene (50 Ma) and continued to a climax during the middle Eocene for exposed volcanic rocks and Oligo-Miocene for plutonic rocks in many parts of Iran (Berberian and King, 1981). These volcanic and plutonic rocks are generally associated with porphyry copper and skarn mineralization in the Sahand-Basman zone, including deposits such as Sungun (Hezarkhani and Williams-Jones, 1998), Sarcheshmeh (Waterman and Hamilton, 1975;Shahabpour, 1982;Hezarkhani, 2006), Miduk (Hassanzadeh, 1993;Taghipour et al, 2008), and many other subeconomic ore bodies (Zarasvandi et al, 2005) The geology of the Dehaj-Sarduiyeh district mainly consists of an Upper CretaceousEocene basic to felsic volcanic-sedimentary complex. Oligo-Miocene granitic rocks intruded into thick sequences (as thick as 15 km) of Eocene lava, pyroclastic, and volcaniclastic rocks as batholiths, stocks, and dykes.…”

“…Tiny grains of other ore minerals are bornite and enargite. Based on Re-Os dating of molybdenite, the hypogene mineralization formed at 12.23 ± 0.07 Ma ( (Taghipour et al, 2008).…”

“…Like other well known porphyry Cu deposits in the Sahand-Bazman magmatic arc zone, the Miduk deposit is a typical porphyry Cu deposit with respect to its ore grade and size, mineralization style, alteration types, igneous rock features, and overall geodynamic setting. The supergene and hypogene mineralization has proven and inferred resources of 170 Mt at 0.86% Cu, 0.007% Mo, 82 ppb Au, and 1.8 ppm Ag (Taghipour et al, 2008); however, resources are known to be considerably higher than 170 Mt, because high-grade hypogene mineralization continues at depths extending greater than 1 km.…”

Two and three-dimensional slope stability analyses of final wall for Miduk mine

“…The orebody contains 170 million tons of ore, with an average grade of 0.86 % Cu, 0.007 % Mo, 82 ppb Au and 1.8 ppm Ag. Supergene enrichment blankets average approximately 50 m thickness and comprise the primary source of Cu ore (Taghipour et al 2008).…”

Chemistry of magmatic and alteration minerals in the Chahfiruzeh porphyry copper deposit, south Iran: implications for the evolution of the magmas and physicochemical conditions of the ore fluids

“…Stöcklin (1968) and Aghanabati (1990)] and location of Chahfiruzeh and Sarcheshmeh porphyry systems. Hamilton, 1975), andesitic dykes in Sungun (Hezarkhani, 2006), and diorite-to quartz-diorite dykes in Miduk (Taghipour et al, 2008). Hasanpour (2010) showed that the andesitic dykes in Sungun postdated the main stage of alteration-mineralization by less than 0.5 Ma.…”