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    江西省村前铜多金属矿床斜长花岗斑岩LA-ICP-MS锆石U-Pb年龄及地质意义

    Zircon LA-ICP-MS U-Pb age of plagiogranite porphyry in the Cunqian copper polymetallic deposit of Jiangxi Province and its geological implications

    • 摘要: 提要:村前铜多金属矿床是产于钦杭成矿带东段的重要的斑岩-矽卡岩矿床,含矿岩体为黑云母斜长花岗斑岩和斜长花岗斑岩,具有多次侵入特点及钙碱性岩石的地球化学特征。本研究采用了LA-ICP-MS技术,首次对含矿的斜长花岗斑岩岩体中的锆石进行了U-Th-Pb同位素分析,获得其成岩年龄为(169.3±1.1)Ma。这一年龄与钦杭成矿带中德兴花岗闪长斑岩、银山石英斑岩、冷水坑花岗斑岩、桐村花岗斑岩等岩体的年龄十分接近,揭示在钦杭成矿带175~156 Ma经历了一次大规模的岩浆侵位与成矿事件,形成了众多与埃达克质或钙碱质花岗岩有关的斑岩-矽卡岩型铜多金属矿床,进一步说明钦杭成矿带在此时期在同一岩浆-动力背景下形成了斑岩-矽卡岩型铜多金属矿成矿系列。

       

      Abstract: Abstract:The Cunqian copper polymetallic deposit is an important porphyry-skarn deposit along eastern Qinhang metallogenic belt. The ore-bearing intrusive body comprises biotite plagiogranite porphyry and plagiogranite porphyry, characterized by repeated invasion and calcium-basic rocks. The LA-ICP-MS technique was used in this study, and U-Th-Pb isotopic analysis was made for zircons from the ore-bearing plagioclase granite porphyry, with the petrogenic age obtained being (169.3 ± 1.1)Ma. This petrogenic age of the ore-bearing rock body is very close to ages of Dexing granodiorite porphyry, Yinshan quartz porphyry, Lengshuikeng granite porphyry and Tongcun granite-porphyry, suggesting that an event of large-scale magmatic emplacement and mineralization took place in 175-156Ma, which led to the formation of many porphyry-skarn copper polymetallic deposits related to adakite or alkali-calcic granite, and implying that the Qinhang metallogenic belt produced a metallogenic series of porphyry-skarn copper polymetallic deposits under the same magma-dynamic background in this period.

       

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