Re-Os and U-Pb geochronology of the Duobaoshan porphyry Cu-Mo-(Au) deposit, northeast China, and its geological significance

The large-scale Duobaoshan porphyry Cu-Mo-(Au) deposit is located at the north segment of the Da Hinggan Mountains, northeast China. Six molybdenite samples from the Duobaoshan deposit were selected for Re-Os isotope measurement to define the mineralization age of the deposit, yieldings a Re-Os isochron age of 475.9. ±. 7.9. Ma (2. σ;), which is accordant with the Re-Os model ages of 476.6. ±. 6.9-480.2. ±. 6.9. Ma. This age is consistent with the age of the related granodiorite porphyry, which was dated as 477.2. ±. 4. Ma by zircon U-Pb analysis using LA-ICP-MS. These ages disagree with the previous K-Ar age determinations that suggest a correlation of intrusive rocks of the Duobaoshan area with the Hercynian intrusive rocks of Carboniferous-Permian age. These ages demonstrate that the Duobaoshan granodiorite porphyry and related Cu-Mo deposit occurred in the Early Ordovician. The rhenium content of molybdenite varies from 290.9 to 728.2. μg/g, with an average content of 634.8. μg/g. The high rhenium content in molybdenite of the Duobaoshan deposit suggests that the ore-forming materials may be mainly of mantle source. © 2013 Elsevier Ltd.