Re-Os Dating of Sulfides from the Volcanogenic Massive Sulfide Deposit at Gacun, Southwestern China |
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| Authors: | Zengqian Hou Shuxian Wang ao Du Xiaoming Qu Weidong Sun |
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| Institution: | Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 10003 7, China [e-mail: ];National Research Center ofGeoanalysis, Chinese Academy of Geological Sciences, Beijing 10003 7, China;China University of Science and Technology, Hefei 230026, China |
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| Abstract: | Abstract. The Re-Os isotopic compositions of sulfide ores were analyzed for the Gacun, a volcanogenic massive sulfide deposit in southwestern China, to constrain the timing of mineralization. Sulfide ores from the deposit have a wide range of Re and Os concentrations, varying from 80.2 to 1543.2 ppb and from 0.307 to 8.83 ppb, respectively, and yielded a limited field of high 187Re/188Os and high 187Os/188Os ratios, ranging from 1452 to 3309 and from 5.77 to 13.24, respectively. All sulfide samples yielded an isochron with an age of 217±28 Ma and an initial 187Os/188Os ratio of around 0.52±0.73. The Re-Os isochron age agrees with ages previously constrained by the other isotopic dating of the host rocks and fossil strata for the deposit. The rhythmic variation in 187Os/188Os and 187Re/188Os ratios within massive sulfide zone records a complicated process for ore-forming fluids episodically vented into the brine pool on the Mesozoic seafloor. |
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| Keywords: | Re-Os isotope mineralization age VMS deposit Gacun China |
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