| 冀北三面井岩体时代、地球化学特征及其地质意义 |
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| 引用本文： | 彭树华,孙立新,时学忠,朱本鸿,任邦方,滕飞.冀北三面井岩体时代、地球化学特征及其地质意义[J].世界地质,2013,32(4):694-706. |
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| 作者姓名： | 彭树华 孙立新 时学忠 朱本鸿 任邦方 滕飞 |
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| 作者单位： | 1. 中国地质调查局天津地质调查中心，天津300170; 2. 河北省勘查地球物理地球化学大队，河北廊坊065000; 3. 昆明理工大学国土资源工程学院，昆明650093 |
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| 基金项目： | 中国地质调查局国土资源调查项目（1212011121078,1212011121072）联合资助 |
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| 摘 要： | 冀北三面井岩体位于华北克拉通北缘，由石英闪长岩组成。为了探讨华北克拉通北缘早古生代演化历史，采用LA--MC--ICP--MS 锆石U--Pb 定年法，获得石英闪长岩206Pb /238U 年龄为471 ± 2 Ma，时代为中奥陶世。岩石为钙碱性系列，轻稀土富集，微量元素Nb、P、Ti、Y、Yb 亏损，Ｒb、Th、K、 Ba、Sr 等元素富集，表明其形成于岛弧或活动大陆边缘环境。锆石Hf 同位素分析表明，锆石εHf ( t) 值为+ 8. 3 ～ + 10. 1，单阶段模式年龄为679 ～ 753 Ma，两阶段模式年龄为807 ～ 921 Ma，其TDM1、TDM2 与岩体形成时间相差较大，岩体源于亏损地幔或从亏损地幔中新生的年轻地壳物质的部分熔融，揭示了华北克拉通北缘存在新元古代地壳增生事件。结合区域地质资料分析，三面井岩体的形成可能与早古生代温都尔庙洋壳向华北克拉通之下的俯冲作用有关。
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| 关 键 词： | 冀北 三面井 石英闪长岩 奥陶纪 锆石U--Pb 年代学 地球化学 |
Age and geochemistry of Sanmianjing pluton in northern Hebei and its geological implication |
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| PENG Shu-hua,SUN Li-xin,SHI Xue-zhong,ZHU Ben-hong,REN Bang-fang,TENG Fei.Age and geochemistry of Sanmianjing pluton in northern Hebei and its geological implication[J].World Geology,2013,32(4):694-706. |
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| Authors: | PENG Shu-hua SUN Li-xin SHI Xue-zhong ZHU Ben-hong REN Bang-fang TENG Fei |
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| Institution: | 1. Tianjin Center of Geological Survey，CGS，Tianjin 300170，China; 2. Hebei Pervence Exploration Geophysical and Geochemistry Survey，Langfang 065000，Hebei，China; 3. Department of Earth Sciences，Kunming University of Science and Technology，Kunming 650093，China |
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| Abstract: | Sanmianjing pluton from northern Hebei was located in the northern margin of North China Craton, which consisted of quartz diorite. With the aim of constraining the tectonic evolution of the northern margin of North China Craton in Early Paleozoic, the quartz-diorite^206rpb/^238 U age was gained by LA-MC-ICP-MS zircon U-Pb dating as 471 ±2 Ma, showing the Middle Ordovican. The pluton has The trace elements are depleted in Nb, P, Ti, Y and Yb, but mianjing pluton formed in island arc or active continental margin to ± 10. 1, their single-stage （ To~1 ） and two-stage （TOM2） mode calc-alkaline characteristics, enriched in LREE. enriched in Rb, Th, K, Ba and Sr, showing Sansettings. Zircon εf（t） values ranged from ± 8.3 1 ages varied from 679 Ma to 753 Ma and from 807 Ma to 921 Ma, respectively, implying that the quartz diorites could be derived from partial melting of a depleted mantle source or a newly accreted crust. Combined with the regional geological data, it is suggested that the quartz diorites formed under an active continental margin setting related to the Early Paleozoic subduction of the Onduermi- ao oceanic crust subducted the northern margin of the North China Craton. |
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| Keywords: | northern Hebei Sanmianjing quartz diorite Ordovican zircon U-Pb chronology geochemistry |
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