Geochronology of the Xingshan molybdenum deposit, Jilin Province, NE China, and its Hf isotope significance
文摘
The Xingshan porphyry Mo deposit is located in the Lesser Xing¡¯an Range-Zhangguangcai Range metallogenic belt, NE China. Mineralization occurred in granodioritic porphyry and monzogranite, which have zircon U-Pb ages of 171.7 ¡À 2.2 Ma and 170.9 ¡À 4.6 Ma, respectively. Molybdenite Re-Os dating indicates that Mo mineralization occurred at 167.3 ¡À 2.5 Ma. These geochronological data suggest that the magmatic and hydrothermal activities of the Xingshan Mo deposit happened during the Middle Jurassic in Mesozoic. Positive ¦ÅHf values (6.2-11.6) and young TDM2 (473-826 Ma) of the monzogranite (XS-3) and granodioritic porphyry (XS-5) indicate that the source materials of Xingshan ore-bearing rocks are the juvenile crust, which mainly accreted on the Songnen block during the Meso-Neoproterozoic. Xingshan porphyry Mo deposits resulted from the magmatism and tectonism induced by the subduction of Paleo-Pacific Ocean.