Fluid Inclusion Studies on Quartz Veinlets at the Yeylagh-e-Gharechi Porphyry Copper Deposit, Arasbaran Metallogenic Belt, Northwestern Iran

Yeylagh-e-Gharechi porphyry copper deposit is located in the Arasbaran metallogenic belt at northwestern Iran, 25 kilometer of Ahar. Porphyry mineralization at the Yeylagh-e-Gharechi deposit occurred in post-Oligocene quartz monzonite and monzonite bodies which was hosted by Eocene volcanic rocks. Mineralization occurred as veins, veinlets and dissemination in hypogene zone. Supergene zone has been demolished by erosion agents. Four types of quartz veinlets are recognized based on mineralogy and relative temporal relationship .distinguished during the study of the deposit. Fluid inclusion studies on fluids trapped in quartz type I (potassic zone) vein and veinlets which were taken from drill core samples indicated a wide range of homogenization temperature in the veinlets from 190o to 520o with salinity of 20-60 wt% NaCl equivalent. Mineralizing fluids density at the deposit was 0.8-1.2 g/cm3. Fluid inclusion studies suggested that Yeylagh-e-Gharechi deposit is probably a porphyry copper deposit. This deposit has many similarity with other copper-gold porphyry deposit in Iran such as Sar Cheshmeh.