Geochemical characteristics of igneous host rocks associated of Lubin-Zardeh epithermal gold deposit, NW of Iran

The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran type. The intrusive rocks are enriched in LILE, LREE and depleted from HFSE, MREE and HREE and Y. A listric-shaped REE pattern and average La/Yb ratios of host rock indicates higher water content and fO2 in the magma and hornblende fractionation. Their relatively low to moderate ISr values (0.7047–0.7051), positive εNd (t = 36 Ma) values (0.39–2.1) and TDM ages of 0.69 to 1.06 Ga, with Pb isotopic ratios of (206Pb/204Pb) i = 18.49–18.68, (207Pb/204Pb) i = 15.58–15.61 and (208Pb/204Pb) i = 38.33–38.77. Based on textural evidence (coarse amphibole crystals), geochemical data (major, trace and Rare earth elements) and isotopic contents of Pb, Sr-Nd, it is suggested that these rocks correspond to geochemical and isotopic compositions of the host rocks of porphyry and epithermal deposits in the Urmia Dokhtar zone of West Alborz-Azerbaijan (Arasbaran) and Eastern Pontides epithermal deposits, Turkey.