Geological characteristics and molybdenite Re-Os age of the Xingjiashan W-Mo deposit in Yantai area, Jiaodong Peninsula, Shandong Province

Located in the Jiaodong metallogenic province, the Xinjiashan ore deposit is the only large-size molybdenum deposit in Shandong Province, and the associated tungsten resources in this ore deposit have already reached middle-scale reserves. This study provides the first high-precision dating of the mineralization age of this ore deposit. Re-Os dating of five molybdenite separates from ores has yielded an isochron age of 157.6±3.9Ma(MSWD=0.24), and a weighted mean age of 161Ma±1.0Ma (MSWD=0.7). The main metallogenic epoch of Jiaodong metallogenic province is 110～130Ma, which means the metallogenic age of W and Mo mineralization in this area is earlier than that of Au. It is indicated that there existed at least two ore-forming periods in Jiaodong, with the former being W, Mo, and the latter being Au. In association with the isotope data obtained from East Nanling, the authors hold that the W metallogenic epochs of the two areas are consistent with each other. This study suggests that there existed an important mineralization epoch during 150～160Ma in eastern China.