投稿时间：2020-08-20
修订日期：2021-11-14
网络发布日期：2022-01-11
中文摘要:江西永平矿床位于钦杭成矿带东段,是该成矿带内矽卡岩型Cu-W共生成矿的典型代表。为查明永平似斑状黑云母花岗岩的源区特征及其与Cu-W矿化的关系,文章对该花岗岩进行了岩石学、锆石U-Pb年代学、微量元素地球化学及Hf同位素研究。结果表明,似斑状黑云母花岗岩的锆石LA-ICP-MS U-Pb年龄为160 Ma,与空间上密切相关的矽卡岩Cu-W矿床(辉钼矿Re-Os年龄为156 Ma)具有密切的时间联系,表明永平Cu-W矿床成岩成矿作用均发生于中晚侏罗世。锆石的Ce4+/Ce3+平均值为283,表明其具有高的氧逸度,指示出很好的Cu成矿潜力。锆石的εHf(t)值为-9.60~-2.27,并且有高w(MgO)(0.84%~1.33%)和Mg#(44~49)值,表明该区花岗质岩浆来源于古老地壳物质的部分熔融,并有地幔物质的加入。通过与区内同期Cu矿化和W-Sn矿化花岗岩对比,成Cu和成Cu-W矿花岗岩的氧逸度高于成W-Sn花岗岩,成Cu-W花岗岩εHf(t)值介于成Cu和成W-Sn花岗岩之间。因此,岩浆高氧逸度和一定比例的壳幔混合可能是形成Cu-W矿的重要条件。
Abstract:The Yongping deposit,located in the eastern of the Qin-Hang metallogenic belt,is a representative deposit of skarn coexisting Cu-W mineralization.To clarify the source characteristics of Yongping porphyritic biotite granite,and to address the relationship between magmatism and Cu-W mineralization,the granite was collected for zircon U-Pb dating,trace element characteristics and Hf isotope analysis.The zircon LA-ICP-MS U-Pb age of porphyritic biotite granite is 160 Ma,which is well coincident with molybdenite Re-Os ages (156 Ma),indicating that the granite and Cu-W mineralization are simultaneously formed in the Middle-Late Jurassic.The average Ce4+/Ce3+ ratios of zircons in the porphyritic biotite granite are 283,which suggest that magma has a high oxygen fugacity and good metallogenic potential.The widely varying εHf(t) values (-9.60 to-2.27) and high w(Mg O)(0.84%~1.33%) and Mg#(44~49) values of the porphyritic biotite granite,indicate that the granitic magma was derived from the partial melting of Neoproterozoic crustal material,with a small amount of mantle components.The granitoid associated with Cu and Cu-W mineralization have higher oxygen fugacity than those associated with W-Sn mineralization.The εHf(t) values of Cu-W granites are between those of Cu granites and W-Sn granites.The high oxygen fugacity of magma and a certain proportion of crust-mantle mixing may be the important conditions for the formation of Cu-W mineralization.
keywords:geochemistry zircon U-Pb ages Hf isotope zircon trace element porphyritic biotite granite Yongping Cu-W deposit
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基金项目:国家自然科学基金重点国际合作研究项目(编号:41820104010)资助
引用文本：
苏蔷薇,毛景文,宋世伟,王训军.2021.江西永平Cu-W矿床成矿岩体的锆石U-Pb年龄、Hf同位素、微量元素特征及其意义[J].矿床地质,40(6):1199~1213SU Qiang-wei,MAO Jing-wen,SONG Shi-wei,WANG Xun-jun.2021.Zircon U-Pb ages, Hf isotope and trace element characteristics of ore-related intrusions in Yongping Cu-W deposit, Jiangxi and their geological significance[J].Mineral Deposits40(6):1199~1213
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