Re-Os dating of porphyry-skarn-stratabound Cu-Au-Mo deposits in the Middle-Lower Yangtze River metallogenic belt, China: Implications for their genesis

摘要

The Middle-Lower Yangtze River metallogenic belt is an important corridor for Cu-Au-Mo-Fe deposits in East China. We obtained eleven molybdenite samples from five skarn-porphyry Cu-Au-Mo deposits and five samples from the Datuanshan stratabound Cu-Au-Mo deposit for Re-Os dating. These sixteen molybdenite samples yield model ages between 129.5 +-1.8 and 137.5 +- 2.0 Ma (2σ) with a mean of 134.3 +- 2.5 Ma. The five samples from the Datuanshan Cu-Au-Mo deposit define an isochron of 134.7 +- 3.2 Ma (2σ) with an initial 187Os of 0.1 +- 8.8 (MSWD = 0.36). These results suggest that stratabound and skarn-porphyry Cu-Au-Mo deposits belong to same metallogenic system rather than two different mineralization events, as previously suggested.