Re-Os ages of molybdenite from the Sibozi-Liubozi molybdenum-copper deposit in Qinglong County of Hebei Province and Its Implications for Metallogeny

Abstract：Located in eastern Yanliao metallogenic belt, the Siboozi-Liubozi molybdenum-copper deposit in Qinglong County is a newly-discovered medium-size molybdenum-copper deposit. Molybdenite occurs as veinlets, stockworks and disseminations in the skarn hosted in quartz sandstone and dolomite of Changcheng System. Molybdenum mineralization is closely related to silicification. Ore bodies occur in stratoid, veined and lenticular forms. Precise Re-Os dating of molybdenite from the molybdenite-quartz vein in ore was studied in this paper. The results show that the Re-Os model ages of seven samples range from (191.6±2.7) Ma to (196.0±2.9) Ma, with the weighted mean age of (194±1) Ma, and the Re-Os model ages of two samples range from (121.1±1.8) Ma to (125.9±1.9) Ma, suggesting that the main metallogenic epoch of the Sibozi-Liubozi molybdenum-copper deposit was formed in the earliest Jurassic period (196～192 Ma) and that molybdenum mineralization was probably related to granite-porphyry (196～190 Ma) intrusive activities of Laoshangjia and Wubozi. Molybdenum metallogenesis of Lower Cretaceous (121～126Ma)?in the ore district is the latest data reported in Yanliao area. The rhenium values of molybdenite samples are in the range of 6.475～6.923μg/g and 38.74～71.358μg/g, implying that Mo and Cu were derived not only from the crust but also from the mantle-crust mixed source.