Molybdenite Re-Os age and metallogeny of the Yueheping skarn molybdenum deposit in Ningshan,southern Qinling

The Yueheping molybdenum deposit is located in the multi-metal metallogenic belt of South Qinling orogenic belt,close to the giant molybdenum mining in eastern Qinling belt.5 molybdenite samples of this deposit yield Re-Os isotopic model ages ranging from 189.8Ma to 195.4Ma,with a weighted mean age of 191.4 ± 1.6Ma.A similar isochron age of 193.6 ± 3.5Ma is also obtained by the isochron regression.This result suggests that the Mo mineralization occurred in Early Jurassic and this ore deposit belongs to the Early Yanshanian large-scale mineralization period in northern China.The Yueheping molybdenum deposit is likely a part of the postcollisional Mo mineralization in the Qinling orogen,which is formed by the collision of the Yangtze and North China plates.On the basis of a summary of previously reported isotopic age data of the Mo deposits in the Qinling area,it is suggested that a mineralization event occurred in Late Indosinian to Early Yanshanian in the Qinling area,but the deposits were probably modified or destroyed in Late Yanshanian events.Hence,the geochronological study of the Yueheping Mo deposit is of significance in the exploration of Mo deposits in south Qinling orogenic belt.