刘铭涛, 刘建明, 薛春纪, 陈向平, 陈志国, 冯宝山. 内蒙古大井铜多金属矿床脉岩LA-ICP-MS锆石U-Pb定年及成矿时代[J]. 地质通报, 2019, 38(8): 1306-1313.
    引用本文: 刘铭涛, 刘建明, 薛春纪, 陈向平, 陈志国, 冯宝山. 内蒙古大井铜多金属矿床脉岩LA-ICP-MS锆石U-Pb定年及成矿时代[J]. 地质通报, 2019, 38(8): 1306-1313.
    LIU Mingtao, LIU Jianming, XUE Chunji, CHEN Xiangping, CHEN Zhiguo, FENG Baoshan. LA-ICP-MS zircon U-Pb dating of dikes in the Dajing copperpolymetallic deposit and a discussion on the metallogenic epoch[J]. Geological Bulletin of China, 2019, 38(8): 1306-1313.
    Citation: LIU Mingtao, LIU Jianming, XUE Chunji, CHEN Xiangping, CHEN Zhiguo, FENG Baoshan. LA-ICP-MS zircon U-Pb dating of dikes in the Dajing copperpolymetallic deposit and a discussion on the metallogenic epoch[J]. Geological Bulletin of China, 2019, 38(8): 1306-1313.

    内蒙古大井铜多金属矿床脉岩LA-ICP-MS锆石U-Pb定年及成矿时代

    LA-ICP-MS zircon U-Pb dating of dikes in the Dajing copperpolymetallic deposit and a discussion on the metallogenic epoch

    • 摘要: 内蒙古林西县大井矿床是与次火山岩有关的热液脉型矿床,矿体受NW向、NWW向断裂控制,产出在二叠系林西组中。用LA-ICP-MS技术,测得成矿前的霏细岩脉和安山玢岩脉中的锆石206Pb/238U年龄分别为164.1±0.8Ma(MSWD=0.60,n=16)和253.8±1.1Ma(MSWD=0.96,n=14)。其中霏细岩锆石年龄表明,其形成可能与西伯利亚板块和蒙古-华北板块之间的鄂霍茨克洋碰撞造山有关;安山玢岩可能与华北板块与西伯利亚板块碰撞造山有关。通过成矿前脉岩的锆石年龄,可以限定大井矿床的成矿时代晚于164Ma。结合前人研究结果,推测大井铜多金属矿床的形成主要受控于晚侏罗世-早白垩世岩浆活动。

       

      Abstract: The Dajing deposit was previously regarded as a magmatic hydrothermal type deposit.The orebodies are controlled by the NW-and NWW-trending faults and occur in Permian Linxi Formation. The zircon samples collected during the research were dated by using LA-ICP-MS zircon U-Pb method, and the authors obtained the following results:the zircon U-Pb ages are 164.1±0.8Ma (MSWD=0.60, n=16) and 253.8 ±1.1Ma (MSWD=0.96, n=14) for felsite dikes and andesite porphyry dikes, respectively. Felsite dikes were formed in a collisional setting probably related to the closure of Mongolia-Okhotsk Ocean and post collision, while andesite porphyry dikes were formed in a tectonic setting possibly related to the collision between Siberian Plate and North China Plate. Based on the zircon U-Pb ages of dikes obtained, the authors have reached the conclusion that the ore-forming process of the Dajing polymetallic deposit occurred later than 164Ma. The most intense volcanic-magmatic activities of the Da Hinggan Mountains took place during Middle Yanshanian period. It is therefore held that the ore-forming process of the Dajing polymetallic deposit occurred approximately in Late Jurassic-Early Cretaceous.

       

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