WANG Hui, WEN Shouqin^*, ZHANG Guangliang, TANG Tieqiao, MA Pengcheng, ZHANG Kailun, LIU Bo

 (School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China)

Abstract: The eastern Ulgen porphyry molybdenum deposit in Erguna City, Inner Mongolia is located in the northern section of the Greater Khingan Mountains. Through field investigation and mineralogical study, it is found that there are obviously different two kinds of molybdenite in the deposit. Combined with data of electron probe analysis, Re-Os isotope test and fluid inclusion test, it is found that the two types of molybdenite have obvious different characteristics in compositions of major elements including S and Mo and trace elements. Two types of molybdenite have respective two Re-Os ages, one is 136.4 Ma, the other is 146.0 Ma. Based on the comprehensive analysis, it is believed that the eastern Ulgen molybdenum deposit was formed in the late Jurassic-Early Cretaceous. Two times of boiling processes resulted in two times of molybdenite mineralization. All evidences indicate that there are two stages of molybdenite mineralization in the deposit.

Keywords: porphyry molybdenum deposit; molybdenite; Re-Os isotopic dating; fluid inclusion; eastern Ulgen