江西德兴地区朱砂红斑岩铜矿成岩成矿年代学特征及其地质意义

Diagenetic and Metallogenic Geochronological Characteristics of Zhushahong Porphyry Copper Deposit in Dexing Area of Jiangxi and Its Implications

江西德兴斑岩铜矿是中国东部大型斑岩铜矿,由朱砂红、铜厂及富家坞三大矿床组成。在前人研究基础上,对德兴地区朱砂红斑岩铜矿含矿花岗闪长斑岩进行锆石SHRIMP U-Pb年代学和磷灰石ID-TIMS U-Pb年代学研究。结果表明:花岗闪长斑岩的锆石SHRIMP U-Pb年龄为(171.3±1.7)Ma,平均标准权重偏差(MSWD)为1.4;热液蚀变磷灰石ID-TIMS U-Pb年龄为(170.6±1.0)Ma,MSWD值为0.49。上述年龄数据表明:朱砂红斑岩铜矿含矿斑岩侵位和铜钼成矿作用均发生在中侏罗世,从岩浆侵位到热液成矿具有较短的岩浆热液演化过程。

Dexing porphyry copper deposit in Jiangxi is one of the largest in the eastern of China.It is composed of Zhushahong,Tongchang and Fujiawu deposits.Based on the petrographic investigation of drill core samples,SHRIMP zircon U-Pb dating and ID-TIMS apatite U-Pb dating for ore-bearing granodiorite porphyry from Zhushahong porphyry copper deposit in Dexing area were presented.The results show that SHRIMP zircon U-Pb age of granodiorite porphyry is（171.3±1.7）Ma with the mean standard weighted deviation（MSWD）of 1.4;ID-TIMS apatite U-Pb age with hydrothermal alteration is（170.6±1.0）Ma with the MSWD of 0.49.The above ages indicate that the emplacement of ore-bearing porphyry from Zhushahong porphyry copper deposit and the mineralization of Cu-Mo develop in Middle Jurassic and are nearly contemporaneous;there is short magmatic-hydrothermal evolution process from magma emplacement to hydrothermal mineralization.