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广东锡坪钼铜多金属矿床位于钦杭成矿带的西南端,为一大型的斑岩型矿床。本文利用辉钼矿Re-Os同位素定年方法对锡坪钼铜多金属矿床4件辉钼矿样品进行了成矿年代学测定,获得的模式年龄为85.15~88.34Ma,加权平均值为86.1±2.3Ma,对应的等时线年龄为89.9±3.4Ma,模式年龄和等时线年龄结果在误差范围内基本一致,指示锡坪钼铜多金属矿床的成矿时限为晚白垩世。锡坪钼铜多金属矿辉钼矿样品的Re含量较低,表明其成矿物质可能主要来自于壳源。钦杭成矿带成岩成矿作用以中生代燕山期为主,存在180~150Ma、110~80Ma两个爆发期,两期成岩成矿作用可能均与太平洋板块的俯冲有一定的关系。锡坪钼铜多金属矿床是在岩石圈伸展减薄环境下发生的大规模成矿作用的产物。
Guangdong Xiping molybdenum copper polymetallic deposits located in the southwestern tip of Qinhang metallogenic belt, is a large porphyry type deposit. In this paper, molybdenite Re-Os isotopic dating method was used to determine the age of molybdenite samples from four molybdenite samples of Xiping porphyry copper-copper polymetallic deposit. The obtained model ages were 85.15 ~ 88.34Ma and the weighted average was 86.1 ± 2.3 Ma. The corresponding isochron age is 89.9 ± 3.4Ma, and the model age and isochron age are basically the same within the error range, indicating that the metallogenic time limit of the Xipin molybdenum-copper polymetallic deposit is Late Cretaceous. The Re content of molybdenite samples from the Xiping molybdenum-copper polymetallic deposit is lower, indicating that the metallogenic materials may be mainly derived from the crust source. The diagenesis and mineralization of the Qinhang metallogenic belt are dominated by the Mesozoic Yanshanian period with 180 ~ 150Ma and 110 ~ 80Ma eruptions. Both diagenesis and mineralization may be related to the subduction of the Pacific plate. The Xiping Molybdenum-Copper Polymetallic Deposit is a product of large-scale metallogenesis that occurs under lithospheric stretch-thinning.