Geology, alteration and mineralization of the Haftcheshmeh Cu-Mo porphyry deposit

The Main Copper belt of Iran that corresponds with the Cenozoic Urumieh-Dokhtar magmatic belt (UDMB) extends for over 2000 km، with an average width of 40 Km، from northwest to southeast Iran، and is characterized by dominantly calc-alkaline volcanic، pyroclastic and intrusive rocks. This belt hosts numerous porphyry-type Cu ± Mo mineralization، but notable are two world-class deposits، Sarcheshmeh (1200 Mt of ore at 0. 69% Cu and 300 ppm Mo) and Sungun (>500 Mt of ore at 0. 69% Cu and ~250 ppm Mo) in the southern and northern of the Cu-Au belt، respectively. There are evidences that the northern part of Iran formed on a separate arc related to the southern lesser Caucasusian subduction zone. The arc extends from northwest Iran to Armenia in the north and contains several porphyry-style mineralizations، including Sungun and Haftcheshmeh in Iran and Kajaran and Dastakert in Armenia. The Haftcheshmeh prospect is a magmatic suite. Intrusions composition is vary from gabbro to granodiorite. The granodiorite intrusion has intruded into the intrusion with gabbro composition. Drilling works has indicated an ellipsoid body with 500×700 dimension at the 700m depth. Potassic، phyllic، propylitic and argillic alteration assemblages are well developed in Haftcheshmeh. Mineralization occurs as disseminated as well as stock works in the granodiorite and the gabbro. Sillica A and D type veinlets are present in this district. On primitive mantle -normalized plots، the porphyritic intrusion shows clear enrichment in LILE، U، Th، Pb and Sr، and depletion in HFSE (Ti، Ta، Nb)، features commonly attributed to subduction- related magmas originated from mantle. The Haftcheshmeh prospect is a typical porphyry deposit in terms of its alteration and mineralization، association with felsic intrusions، predominance of quartz veinlets and subduction related tectonic setting.