| 西藏双湖地区南措铜金矿区花岗闪长岩锆石U-Pb年代学、岩石地球化学及成因 |
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| 引用本文： | 王启,孙丰月,王琳琳,王力,张志颖.西藏双湖地区南措铜金矿区花岗闪长岩锆石U-Pb年代学、岩石地球化学及成因[J].世界地质,2018,37(2):399-408. |
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| 作者姓名： | 王启 孙丰月 王琳琳 王力 张志颖 |
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| 作者单位： | 吉林大学 地球科学学院, 长春 130061 |
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| 基金项目： | 中国地质调查局地质调查项目（12120114080801）和国家自然科学基金项目（41272093）联合资助. |
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| 摘 要： | 对南措铜金矿区与成矿相关的黑云母花岗闪长岩体进行了岩相学、锆石U-Pb年代学、岩石地球化学等方面的研究。结果表明:该岩体年龄为153.40±0.67 Ma,属晚侏罗世。岩石为准铝质-过铝质岩石,属钙碱性系列。LaN/YbN=9.31~12.65,轻重稀土元素分馏明显,δEu=1.21~1.66,Eu表现为正异常;样品微量元素表现为相对富集大离子亲石元素(LILE)K、与高场强元素(HFSE)Sr、Zr,而亏损高场强元素(HFSE)U、Nb、Ce、Nd、P的特征。岩体具有I型花岗岩特征。样品Zr/Hf值为42.23~45.82,平均值为44.2;Rb/Sr比值为0.07~0.19,平均值为0.13;Nd/Th值为1.65~2.18,平均为1.99,具壳源岩浆的特征,并有地幔物质混入。样品的Mg#值为49.80~57.22,Sr值为443.3~874.9,Yb值为0.80~1.39,Y值为8.96~16.60,Na2O/K2O2(2.18~2.97),为洋壳型埃达克岩,并在上升过程中可能有少量地幔楔物质混入。结合前人研究成果认为,该花岗闪长岩形成于晚侏罗世班公湖—怒江洋盆向北俯冲的火山弧环境。
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| 关 键 词： | 南措铜金矿区 黑云母花岗闪长岩 岩石成因 锆石U-Pb年龄 地球化学特征 班公湖-怒江成矿带 |
| 收稿时间： | 2017-12-15 |
| 修稿时间： | 2018-02-21 |
Zircon U-Pb dating,geochemical characteristics and petrogenesis of granodiorite in Nancuo Cu-Au mining area,Shuanghu,Tibet |
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| WANG Qi,SUN Feng-yue,WANG Lin-lin,WANG Li,ZHANG Zhi-ying.Zircon U-Pb dating,geochemical characteristics and petrogenesis of granodiorite in Nancuo Cu-Au mining area,Shuanghu,Tibet[J].World Geology,2018,37(2):399-408. |
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| Authors: | WANG Qi SUN Feng-yue WANG Lin-lin WANG Li ZHANG Zhi-ying |
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| Institution: | College of Earth Sciences, Jilin University, Changchun 130061, China |
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| Abstract: | Petrography,LA-ICP-MS zircon U-Pb dating and geochemical data of biotite granodiorite in Nancuo Cu-Au mining area related to mineralization have been studied.The results show that the diagenetic age of the biotite granodiorite is 153.40 ±0. 67 Ma,belonging to Late Jurassic.And the biotite granodiorites are calc-alkalineseries and quasi aluminum to peraluminous rocks. There is significant fractionation between LREE and HREE,with LaN/YbN=9.31~12.65,and there is positive anomaly for Eu,with δEu=1.21~1.66. For trace elements,the biotite granodiorite is enriched in LILE for K and HFSE for Sr, Zr. But depleted in HFSE for U, Nb, Ce, Nd and P.Characteristics of I type granite are presented in the rock mass. The Zr/Hf value of the sample is 42.23~45.82,with an average of 44.2,the ratio of Rb/Sr is 0.07~0.19,with an average value of 0.13,and the value of Nd/Th is 1.65~2.18,with an average of 1.99,indicating crust derived magma with mantle materials mixed. The Mg# value of the sample is 49.80~57.22,the Sr value is 443.3~874.9,the Yb value is 0.80~1.39,the Y value is 8.96~16.60,and Na2O/K2O > 2(2.18~2.97),indicating oceanic crust adakites,with a small amount of mantle wedge material mixed during the rising process. Combined with previous research,it is suggested that the granodiorite formed in volcanic arc environment during northward subduction of Bangonghu-Nujiang oceanic basin,in Late Jurassic. |
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| Keywords: | Nancuo Cu-Au mining area biotite granodiorite petrogenesis zircon U-Pb ages geochemical characteristics Bangonghu-Nujiang metallogenic belt |
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