| 太行山木吉村斑岩铜(钼)矿床岩石地球化学、Sr-Nd-Pb同位素特征及其地质意义 |
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| 引用本文： | 曲凯,董国臣,李胜荣,申俊峰,王艳娟,王霞,罗薇.太行山木吉村斑岩铜(钼)矿床岩石地球化学、Sr-Nd-Pb同位素特征及其地质意义[J].现代地质,2014,28(3):449-460. |
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| 作者姓名： | 曲凯 董国臣 李胜荣 申俊峰 王艳娟 王霞 罗薇 |
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| 作者单位： | (1天津地质矿产研究所，天津300170；2中国地质大学(北京)地球科学与资源学院，北京100083；3天津国际矿业权交易所，天津300210) |
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| 基金项目： | 国家自然科学重点基金项目(90914002);教育部长江学者和创新团队发展计划资助项目(IRT1083);高等学校“111”计划项目(B07011);中国地质调查局项目“晋冀成矿区资源远景调查评价”(1212011120755) |
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| 摘 要： | 木吉村斑岩铜(钼)矿床位于太行山北段涞源杂岩体的腰部，是太行山构造-岩浆-成矿带的一个重要矿床。在野外调研的基础上，对木吉村斑岩铜(钼)矿床含矿岩体进行了系统的岩石学、地球化学和Sr-Nd-Pb同位素研究。结果表明：木吉村矿床的含矿岩体闪长玢岩为高钾钙碱性I型侵入岩，具有较高的SiO2、Al2O3、Sr含量和Sr/Y比值以及(La/Yb)N，较低的Yb、Y的特征；稀土元素配分曲线呈右倾趋势，轻稀土相对富集，轻重稀土分异明显，具微弱的正Eu异常；微量元素蛛网图中富集大离子亲石元素Ba、K、U、Sr，亏损高场强元素Nb、Ta、P、Ti，总体显示出与埃达克岩相似的地球化学特征。闪长玢岩的ISr为0.705 386~0.706 838，εNd(t)为-16.7~-14.9，208Pb/204Pb、207Pb/204Pb、206Pb/204Pb的平均值分别为36.614、15.226、16.545，与木吉村矿床矿石中的硫化物铅同位素数值基本一致，Sr-Nd-Pb同位素共同表明其岩浆形成可能与有深源基性物质参与的古老下地壳部分熔融有关。结合研究区地质背景，认为木吉村含矿岩体可能主要来自古老下地壳的部分熔融，并受到幔源物质的混染作用。
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| 关 键 词： | 斑岩型铜(钼)矿床 地球化学 Sr-Nd-Pb同位素 木吉村 太行山 |
Lithogeochemistry and Sr-Nd-Pb Isotopic Characteristics of Mujicun Porphyry Cu-Mo Deposit in Taihang Mountains and Their Significances |
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| QU Kai,DONG Guo-chen,LI Sheng-rong,SHEN Jun-feng,WANG Yan-juan,WANG.Lithogeochemistry and Sr-Nd-Pb Isotopic Characteristics of Mujicun Porphyry Cu-Mo Deposit in Taihang Mountains and Their Significances[J].Geoscience——Journal of Graduate School,China University of Geosciences,2014,28(3):449-460. |
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| Authors: | QU Kai DONG Guo-chen LI Sheng-rong SHEN Jun-feng WANG Yan-juan WANG |
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| Institution: | (1Tianjin Institute of Geology and Mineral Resources, Tianjin300170, China; 2School of Earth Sciences and Resources, China University of Geosciences, Beijing100083, China;3Tianjin International Mining Exchange, Tianjin300210, China) |
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| Abstract: | Mujicun porphyry copper-molybdenum deposit, located in the northern section of Taihang Mountains, is an important ore deposit in the Taihang tectonic-magmatic-metallogenic belt. This article is based on the particular field works and systematic analysis of petrology, geochemical data and Sr-Nd-Pb isotopes. The result shows the ore-bearing diorite-porphyry of Mujicun belonging to the high-K calc-alkaline I-type intrusive rock. Geochemical analysis shows that the diorite-porphyry is rich in SiO2, Al2O3 and Sr, a high ratio of Sr/Y, (La/Yb)N, low in Yb and Y. All the ore-bearing porphyries in the study area have similar distribution of rare earths and trace elements, with right-oblique curve, and unclear postive Eu anomalies. It is characterized by enriched large-ion lithophile elements of Ba, K, U, Sr and depleted high field strength elements such as Nb, Ta, P and Ti with adakite affinity in geochemical characteristic. The diorite porphyry has ISr ratios of 0.705 386 to 0.706 838，εNd(t) values of -16.7 to -14.9. The averages of 208Pb/204Pb, 207Pb/204Pb and 206Pb/204Pb ratios are 36.614, 15.226 and 16.545, respectively, similar to those lead isotope ratios in ore of Mujicun deposit. Sr-Nd-Pb isotopes show that the formations of the magma were probably related to origin of partial melting of lower crust with mantle materials contribution. Combining with the geological background of the study area, the authors considered that the Mujicun ore-bearing diorite porphyry possibly resulted from partial melting in lower crust with the mantle mass exchange. |
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| Keywords: | porphyry Cu-Mo deposit geochemistry Sr-Nd-Pb isotopes Mujicun Taihang Mountains |
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