The molybdenite Re-Os age and genetic analysis of the Shangjiazhuang Mo deposit in Jiaodong area

Abstract：The Shangjiazhuang Mo deposit is hosted in the porphyritic granodiorite which belongs to Weideshan Late Yanshanian ultra unit. It is controlled by the fractures in the interior of the magmatic body and in NW direction. The main ore bodies assume stratoid and large vein forms, and are characterized by branching and recombination as well as expansion and pinch-out. Re-Os dating of three molybdenite separates from ores has yielded weighted ages (115.5±1.6)Ma～(117.6±1.6)Ma, and a weighted mean age of (116.4±1.6)Ma, implying that the metallogenic epoch of Mo is nearly identical with the large-scale metallogenic epoch of Au in Jiaodong area, and nearly the same as the diagenetic epoch of their country rock—Yingpan unit of Weideshan super unit. It is proved that there existed a series of Au and Mo ore-forming processes which occurred almost in the same metallogenic epoch and were related to Weideshan granite in Jiaodong area.