ORIGINAL PAPER Aspects of magmatic–hydrothermal evolution of Kahang porphyry copper deposit, Central Iran Mehdi Azadi & Mirsaleh Mirmohammadi & Ardeshir Hezarkhani Received: 7 January 2014 /Accepted: 26 June 2014 # Saudi Society for Geosciences 2014 Abstract Kahang porphyry copper deposit in Isfahan Prov- ince, Iran, is located in the middle of Urmia-Dokhtar Mag- matic Arc. Petrographic studies revealed that igneous rocks in the eastern part of the deposit are divided into three types: host rocks, mineralizing stocks, and post-mineralization barren dikes. Host rocks are mainly Paleocene-Eocene aged, ranging in composition from andesite through quartz-andesite to trachyte-andesite and tuff. Oligo-Miocene quartz-diorite– granodiorite and late dacite have intruded into these volcanic rocks, and are cut by barren andesitic and dacitic dikes. Quartz-diorite has composed more than 70 % of the main mineralizing stock, followed by dacite and less commonly by granodiorite. Geochemistry of plutonic and volcanic rocks confirms that these rocks were crystallized from a single calk- alkaline magma through the differentiation process. Intensive hydrothermal alteration in the deposit is characterized by outward zoning from potassic (biotitic), overprinted by phyllic, quartz-sericitic, to propylitic (chloritic-calcitic), and argillic (jarositic) alteration. Potassic alteration in depths less than 730 m is mainly biotitic, and has no K-feldspar. But, in deeper depths, K-feldspar, quartz, and biotite form the typical potassic alteration zone. The most extensive alteration type in the deposit is phyllic that has mainly affected mineralizing dacitic rocks. Six main groups of veins and breccias were identified related to alteration processes. These groups, from oldest to youngest types, are: Bt-M-, A-, B-, P-, D-T-, and L- type veins and breccias. Fluid inclusion studies on mineralized quartz veins in potassic zone show that mineralization has occurred in a minimum temperature, pressure, and depth of 415 °C, 340 bars, and 1.3 km, respectively. Keywords Porphyry . Petrology . Fluid inclusion . Kahang . Central Iran Introduction Kahang porphyry copper deposit (PCD) is located almost in the middle of the Urmia-Dokhtar Magmatic Arc (UDMA), 73 km north east of Isfahan City. Although all Iranian porphy- ry deposits are located on this magmatic arc, Kahang is the first porphyry deposit explored in this part of the arc (Fig. 1). Regional exploration of copper in this region goes back to the early 1970s but after Iranian Revolution, the exploration ac- tivities were abandoned until 2001 when Rio Tinto carried out geochemical exploration through stream and lithogeochemical sampling (NICICo 2011). Although it was proved that Kahang is a porphyry system, they decided that Kahang is not a priority for future detailed explorations. A private Iranian company (Dorsa Pardaze) in 2005 started the new plan of exploration by geological, geochemical, and geophysical sur- veying, and 3,800 m of core drilling. Finally, in the last 3 years (since 2011) up to now, the National Iranian Copper Industries Company (NICICo) has drilled about 40,000 m bore holes in this deposit (750 m long at most), and data obtained from these drillings have been used in the present study. During 2005 to 2011, former workers on Kahang investi- gated the petrology and alteration mineralogy of the deposit, but few of them have published their results. Based on the earliest available drilling information, mineral resource esti- mation of Kahang (Afzal 2009) demonstrated that this deposit contains 38.74 million tons of sulfide copper ore with an average grade of 0.59 % Cu. He divided Kahang into three parts: Eastern, Central, and Western Kahang. Farahani (2008) M. Azadi (*) : M. Mirmohammadi Department of Mining Engineering, Faculty of Engineering, University of Tehran, POB 11155-4563, Tehran, Iran e-mail: mehdiazadi@ut.ac.ir A. Hezarkhani Department of Mining and Metallurgical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran Arab J Geosci DOI 10.1007/s12517-014-1528-2