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岩石学报 2012
Re-Os dating of the molybdenite from the Jinchuantang tin-bismuth deposit in Hunan Province and its geological significance
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Abstract:
The Dongpo ore field is in the western part of the Nanling polymetallic metallogenic belt, which is located in the intersection between Yangtze block and Cathaysian block. There are a series of large-and medium-sized W-Sn-Mo-Bi polymetallic deposits distributed around the Qianlishan granite in the Dongpo ore field. The Jinchuantang deposit is a large-sized skarn-type tin-bismuth deposit in the Dongpo ore field. Direct Re-Os dating on molybdenites collected from the skarn ore in the Jinchuantang deposit have been carried out, in order to further restrict the age of mineralization. The results show that Re-Os model ages range from 157.2±2.8Ma to 162.4±2.4Ma, with an average of 159.8±2.9Ma, and give an isochron age of 158.8±6.6Ma. Combined with the Re-Os isochron age (151.0±3.5Ma) of Shizhuyuan deposit and zircon SHRIMP U-Pb ages (152±2Ma) of the Qianlishan granite, it is suggested that the mineralization of the Jinchuantang Sn-Bi deposit is temporally and genetically related to the granite in this area. Based on previous studies, petrologenesis and metallogenesis of the Dongpo ore field, including the Jinchuantang deposit, mainly occurred 149~161Ma, which is similar to the large-scale tungsten-tin polymetallic mineralization (150~160Ma) in the Nanling region. Coupled with previous studies in this region, it is suggested that mantle components were extensively involved in the petrologenic and metallogenic processes of the Mesozioc W-Sn polymetallic ore district, southern Hunan Province, indicating that the Middle-Late Jurassic explosive mineralization of this region is probably as results of crust-mantle interactions under a geodynamic setting of the lithospheric thinning and extension.
