| 青海阿尼玛卿蛇绿混杂岩带西段哥日卓托杂岩体年代学、地球化学及Hf同位素 |
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| 引用本文： | 刘金龙,孙丰月,李良,赵菲菲,王英德,王硕,张宇婷.青海阿尼玛卿蛇绿混杂岩带西段哥日卓托杂岩体年代学、地球化学及Hf同位素[J].地球科学,2015,40(6):965-981. |
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| 作者姓名： | 刘金龙 孙丰月 李良 赵菲菲 王英德 王硕 张宇婷 |
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| 作者单位： | 吉林大学地球科学学院，吉林长春 130061 |
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| 基金项目： | 中国地质调查局项目“柴达木周缘及邻区成矿带地质矿产调查评价”(No．1212011086020)． |
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| 摘 要： | 布青山构造混杂岩带中的哥日卓杂岩体与区域构造线方向不一致，属于典型的“钉合岩体”，对限定地体拼贴或增生的时间上限具有特殊的构造年代学意义.锆石LA-ICP-MS U-Pb定年结果显示岩体形成于晚三叠世中期(似斑状花岗岩形成于227 Ma，闪长岩形成于224 Ma).在地球化学上，似斑状花岗岩为高钾钙碱性系列，高Sr(479~573 μg/g)，低Yb(1.03~1.20 μg/g)，Mg#值为48.7~51.8，判断岩石属于埃达克岩类.岩石的εHf(t)值为-2.40~2.98，判断岩石源于加厚陆壳部分熔融.闪长岩Ti/Yb值为1 930~2 178，Nb/Ta值为15.9~17.4，属混合成因.综合前人研究成果，哥日卓托杂岩体形成于古特提斯洋闭合后碰撞环境，并且标志同碰撞到后碰撞的构造体制转换.
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| 关 键 词： | 锆石U-Pb年龄 锆石Hf同位素 埃达克岩 地球化学 地质年代学 |
| 收稿时间： | 2014-09-15 |
Geochronology,Geochemistry and Hf Isotopes of Gerizhuotuo Complex Intrusion in West of Anyemaqen Suture Zone |
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| Liu Jinlong,Sun Fengyue,Li liang,Zhao Feifei,Wang Yingde,Wang Shuo,Zhang Yuting.Geochronology,Geochemistry and Hf Isotopes of Gerizhuotuo Complex Intrusion in West of Anyemaqen Suture Zone[J].Earth Science-Journal of China University of Geosciences,2015,40(6):965-981. |
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| Authors: | Liu Jinlong Sun Fengyue Li liang Zhao Feifei Wang Yingde Wang Shuo Zhang Yuting |
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| Abstract: | The Gerizhuotuo complex intrusion, a typical 'stitching pluton' with its long axis cutting regional structural lines, is significant in tectonic geochronology for providing an upper-age for the timing of plate collision. The zircon U-Pb dating results indicate that the pluton was formed in 227-224 Ma. Geochemically, porphyritic granite falls into the high-K calc-alkaline series, with high Sr(479-573 μg/g) and low Yb(1.03-1.20 μg/g) and Mg#(48.7-51.8), being of the characteristics of adakitic rocks. The in situ zircon εHf(t) value varies from -2.40 to 2.98, which suggests that the primary magma was derived from partial melting of lower crustal materials. Diorite also shows high-K calc-alkaline affinitie, with a Ti/Yb ratio ranging from 1 930 to 2 178, Nb/Ta ratio ranging from 15.9 to 17.4. It is suggested that a mixture, between basaltic magma derived from partial melting of metasomatized mantle and acidic magma derived from crustal material, produced the dioritic magma. It is concluded that the pluton was formed in a post-collisional tensional environment. |
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| Keywords: | zircon U-Pb age zircon Hf isotope adakiteic rock geochemistry geochronology |
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