Geochemistry, mineralization and alteration zones of darrehzar porphyry copper deposit, Kerman, Iran

The goal of this study is focused on alteration, mineralization and geochemistry of Darrehzar porphyry copper deposit which is situated in the Central Iranian Tectono-Volcanic Belt. This deposit is associated with an Oligocene granodiorite stock which intruded Eocene Volcano-Sedimentary and Cretaceous carbonate rocks. Four distinct types of hypogene alterations are recognized at Darrehzar: potassic, phyllic, argillic and propylitic. Copper mineralization was accompanied mainly by phyllic and to a lesser extent potassic, alteration. In the potassic alteration zone, enrichment of K and depletion of Na, Ca, Mn and Fe took place. These changes attended replacement of plagioclase and amphibole by K-feldspar and biotite, respectively. Potassic alteration was associated with a major addition of Cu, as evident from the occurrence of disseminated chalcopyrite and bornite in this zone. Phyllic alteration was accompanied by depletion of Na, K, Fe and Ba and enrichment of Si and Cu. Losses of Na, K and Fe reflect sericitization of alkali feldspar and destruction of ferromagnesian minerals. The addition of Si is consistent with widespread silicification, which is a major feature of phyllic alteration, as well as the addition of Cu mobilized from the potassic zone. Pertographic studies of this porphyry copper deposit indicate that granodiorite association is mainly composed of plagioclase, quartz, orthoclase, biotite, sericite. The main mineralization-related alteration episodes (potassic, phyllic, argillic, propylitic) have been studied in terms of mass transfer and element mobility during the hydrothermal evolution of the Darrehzar copper deposit.