| 东准噶尔奥依托浪格地区石炭纪双峰式火山岩地球化学特征及其构造意义 |
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| 引用本文： | 邹国庆,余牛奔,孙国庆,黄修保,尼加提·阿布都逊,卢观送.东准噶尔奥依托浪格地区石炭纪双峰式火山岩地球化学特征及其构造意义[J].吉林大学学报(地球科学版),2021,51(2):455-472. |
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| 作者姓名： | 邹国庆 余牛奔 孙国庆 黄修保 尼加提·阿布都逊 卢观送 |
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| 作者单位： | 1. 江西省地质矿产勘查开发局赣西北大队, 江西 九江 332000;2. 江西省地质矿产勘查开发局, 南昌 330002;3. 新疆大学地质与矿业工程学院, 乌鲁木齐 830047;4. 新疆中亚造山带大陆动力学与成矿预测自治区重点实验室, 乌鲁木齐 830047 |
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| 基金项目： | 中国地质调查局项目(DD20190368)。 |
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| 摘 要： | 本文对东准噶尔造山带三塘湖盆地西北缘奥依托浪格地区石炭纪巴塔玛依内山组进行了火山岩地质、岩相学、地球化学特征研究，并结合相关年代学成果，探讨了火山岩成因、形成环境与东准噶尔造山带构造演化。研究认为：该区石炭纪巴塔玛依内山组火山岩具明显的陆相火山岩、双峰式火山岩特征，岩石组合基性端元以玄武岩为主，酸性端元为珍珠岩、英安岩；主量元素特征显示基性端元为钙碱—碱性性质，酸性端元珍珠岩、英安岩分别属于碱性、拉斑性质；微量元素特征显示基性端元相对富集Ba、K、Sr等大离子亲石元素（LILE），亏损Th、Nb、Nd等高场强元素（HFSE），酸性端元强烈亏损Ba、Nb、Sr、Sm、Ti等元素，富集K元素；稀土元素显示两端元均为轻稀土元素（LREE）相对富集、重稀土元素（HREE）相对亏损特征；珍珠岩主、微量元素特征与整体具有明显差异。综合研究表明：该双峰式火山岩基性端元来源于地幔岩的部分熔融，酸性端元英安岩来源于基性端元的分离结晶作用，珍珠岩则来源于下地壳的部分熔融；地球动力学背景为俯冲洋壳的拆沉作用，造成软流圈热源上涌，引发地幔岩的部分熔融与岩石圈的伸展减薄，进而诱发下地壳镁铁质岩的减压熔融；构造环境为后碰撞伸展阶段晚期，并指示了板块链式缝合的特点。
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| 关 键 词： | 东准噶尔造山带 石炭纪 双峰式火山岩 地球化学 构造意义 |
| 收稿时间： | 2020-01-08 |
Geochemical Characteristics and Tectonic Significance of Carboniferous Bimodal Volcanic Rocks in Aoyituolangge Area,Eastern Junggar |
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| Zou Guoqing,Yu Niuben,Sun Guoqing,Huang Xiubao,Nijiati·Abuduxun,Lu Guansong.Geochemical Characteristics and Tectonic Significance of Carboniferous Bimodal Volcanic Rocks in Aoyituolangge Area,Eastern Junggar[J].Journal of Jilin Unviersity:Earth Science Edition,2021,51(2):455-472. |
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| Authors: | Zou Guoqing Yu Niuben Sun Guoqing Huang Xiubao Nijiati·Abuduxun Lu Guansong |
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| Institution: | (Northwestern Jiangxi Geological Party,Bureau of Geology and Exploration and Development of Mineral Researches of Jiangxi Province,Jiujiang 332000,Jiangxi,China;Bureau of Geology and Exploration and Development of Mineral Researches of Jiangxi Province,Nanchang 330002,China;College of Geology and Mining Engineering,Xinjiang University,Urumqi 830047,China;Key Laborary of Orogenic Belts Continental Dynamics and Metallogenic Prediction,Xinjiang Autonomous Region,Urumqi 830047,China) |
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| Abstract: | In this paper, the geological, petrological, and geochemical characteristics of volcanic rocks of the Batamayineishan formation are studied in the Aoyituolangge area at the northwestern margin of Santanghu basin of the eastern Junggar orogenic belt, and the genesis, formation environment, and tectonic evolution of the eastern Junggar orogenic belt are discussed in combination with the relevant chronological results. It is concluded that the Carboniferous volcanic rocks in this area have obvious characteristics of continental volcanic rocks and bimodal volcanic rocks. The basic end member of the rock combination is mainly basalt, and the acid end members are perlite and dacite. The characteristics of the major elements show that the basic endmembers have calc-alkaline-alkaline properties;While the acidic endmembers of perlite and dacite have alkaline and freckling properties respectively. The characteristics of trace elements show that the fundamental end elements are relatively rich in LILE, such as Ba, K, Sr, etc., while Th, Nb, Nd, and other high-field strength elements(HFSE) are poor. Among the acidic end elements, Ba, Nb, Sr, Sm, Ti and other elements are strongly depleted, while K is more enriched. The analysis of rare earth elements show that LREE at both ends are relatively enriched, while HREE are relatively depleted. The main and trace elements characteristics of perlite are obviously different from the whole. The geochemical characteristics indicate that the basic end members of the bimodal volcanic rocks came from the partial melting of mantle rocks, the acidic end member of dacite came from the separation and crystallization of the basic end members, and the perlite came from the partial melting of the lower crust. The geodynamic background was the subduction of oceanic crust, which caused the upwelling of asthenosphere heat source, the partial melting of mantle rocks, the extensional thinning of lithosphere, and the decompression and melting of the mafic rocks in the lower crust. The tectonic environment was late in the post-collision extension stage, showing the characteristics of plate chain suture. |
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| Keywords: | Eastern Junggar orogenic belt Carboniferous bimodal volcanic rocks geochemistry tectonic significance |
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