Geochemical and fluid inclusion studies of Kalchuyeh Cu-Au epithermal mineralization in the central part of the Urumieh-Dokhtar magmatic arc

The Kalchuye Cu-Au deposit is located in the central part of the Urumieh – Dokhtar magmatic arc. This mineralization is mainly hosted by diorite, quartz diorite and andesite rocks. The mineralization is characterized by chalcopyrite, pyrite, galena and magnetite in the hypogen stage followed by chalcocite, covellite, malachite and goethite in supergen stage. According to the geochemical studies, the Lan/Ybn ratio is between 2.2 to 6.3 and Eu/Eu* varies from 0.7 to 1.1; so that intrusions which are the host of mineralization in the Kalchuye region represent characteristics of magmas in the subduction zone (enrichment of LILE, depletion of HFSE in association with negative Ti anomaly). Fluid inclusion data show the temperature of 150-310 ˚C, salinity of 0.1- 4 (wt%NaCl eq.) and depth of 400m, approximately, for the Klchuyeh deposit. Fluid evolution in the Kalchuye exhibits cooling, surface dilution and boiling. Evidences such as bounded and comb textures in quartz, bladed calcite, hydrothermal breccia, propelitic alteration and fluid inclusion information such as temperature and salinity prove the low-sulfidation epithermal nature for the Kalchuye deposition.