| 中天山地块暗色岩墙LA-ICP-MS锆石U-Pb年龄和岩石地球化学特征 |
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| 引用本文： | 尹继元1,2,陈 文1, 肖文交2,3, 张 斌1, 蔡克大3, 孙敬博1, 张 彦1,杨 静1, 杨 莉1, 刘新宇1, 沈 泽1. 中天山地块暗色岩墙LA-ICP-MS锆石U-Pb年龄和岩石地球化学特征[J]. 地质通报, 2015, 34(08): 1470-1481. |
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| 作者姓名： | 尹继元1 2 陈 文1 肖文交2 3 张 斌1 蔡克大3 孙敬博1 张 彦1 杨 静1 杨 莉1 刘新宇1 沈 泽1 |
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| 作者单位： | 1.中国地质科学院地质研究所,同位素热年代学实验室,大陆构造与动力学国家重点实验室,北京 100037;2.中国科学院地质与地球物理研究所,岩石圈演化国家重点实验室,北京 100029;3.中国科学院新疆矿产资源研究中心,新疆 乌鲁木齐830011 |
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| 摘 要： | 中天山地块发育有大量的暗色岩墙，主要走向为北北西。对中天山暗色岩墙进行LA-ICP-MS锆石U-Pb测年，获得的年龄为304.8±1.5Ma，表明其形成于晚石炭世。这些暗色岩墙具有较高的SiO2，较低的Mg、Cr、Ni含量。它们富集大离子亲石元素（Rb、Ba、Th），亏损高场强元素（Nb、Ta、Ti），显示俯冲相关特征。上述特征暗示，中天山暗色岩墙可能是由俯冲板片流体交代的地幔楔部分熔融形成的。这一发现表明，准噶尔洋的闭合应该发生在晚石炭世之后。
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| 关 键 词： | 中天山 暗色岩墙 LA-ICP-MS 锆石U-Pb测年 地球化学 构造背景 |
LA-ICP-MS zircon U-Pb age and geochemistry of the dark dykes in Central Tianshan Block |
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| YIN Jiyuan1,2, CHEN Wen1, XIAO Wenjiao2,3, ZHANG Bin1, CAI Keda3, SUN Jingbo1,ZHANG Yan1, YANG Jing1, YANG Li1, LIU Xinyu1, SHEN Ze1. LA-ICP-MS zircon U-Pb age and geochemistry of the dark dykes in Central Tianshan Block[J]. Geological Bulletin of China, 2015, 34(08): 1470-1481. |
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| Authors: | YIN Jiyuan1 2 CHEN Wen1 XIAO Wenjiao2 3 ZHANG Bin1 CAI Keda3 SUN Jingbo1 ZHANG Yan1 YANG Jing1 YANG Li1 LIU Xinyu1 SHEN Ze1 |
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| Affiliation: | 1. Laboratory of Isotope Thermochronology, State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;2. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;3. Xinjiang Research Center for Mineral Resources, Chinese Academy of Sciences, Urumqi 830011, Xinjiang, China |
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| Abstract: | The NNW-trending dark dykes widely occur in Central Tianshan Mountains. The LA-ICP-MS zircon U-Pb dating of dark dyke yielded a weighted mean 206Pb/238U age of 304.8±1.5Ma, suggesting that they were generated in Late Carboniferous. The dark dykes are characterized by low Mg, Cr and Ni values. These samples are enriched in LILEs (e.g., Rb，Ba，Th) and depleted in HFSEs (e.g., Nb, Ta, Ti). The dark dykes were likely generated by interaction of mantle wedge with fluids derived from dehydration of the subducting slab. The closure of the Junggar Ocean probably terminated after Late Carboniferous. |
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| Keywords: | Central Tianshan Mountains dark dyke LA-ICP MS zircon U-Pb dating geochemistry tectonic setting |
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