| 新疆阿吾拉勒山西段下二叠统陆相火山岩岩石地球化学特征、成因及构造背景 |
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| 引用本文： | 赵军,张作衡,张贺,刘敏,洪为,蒋宗胜.新疆阿吾拉勒山西段下二叠统陆相火山岩岩石地球化学特征、成因及构造背景[J].地质学报,2013,87(4):525-541. |
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| 作者姓名： | 赵军 张作衡 张贺 刘敏 洪为 蒋宗胜 |
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| 作者单位： | 长安大学地球科学与资源学院，西安, 710054；中国地质大学（北京）地球科学与资源学院，北京，100083;中国地质科学院矿产资源研究所，北京，100037;中国地质大学（北京）地球科学与资源学院，北京，100083;中国地质科学院矿产资源研究所，北京，100037;中国地质科学院矿产资源研究所，北京，100037;中国地质科学院矿产资源研究所，北京，100037 |
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| 摘 要： | 新疆阿吾拉勒山西段是伊犁石炭-二叠纪裂谷的重要组成部分，本文对该区下二叠统典型的双峰式玄武岩-流纹岩组合进行了系统的岩相学和岩石地球化学研究。岩石整体高Na2O、高Al2O3、低TiO2、富碱。玄武岩富集大离子亲石元素Ba、K、LREE和P，亏损高场强元素Th、U、Ta、Nb。粗面斑岩和流纹斑岩富集大离子亲石元素Rb、K、LREE、高场强元素Th、Zr、Hf，亏损Ta、Nb、Sr、Ti和P。玄武安山玢岩的蛛网图与粗面斑岩和流纹斑岩较为一致，但少量元素的特征与玄武岩相似。玄武岩浆来源于弱亏损地幔，并受到了下地壳物质的混染，而玄武安山玢岩、粗面斑岩和流纹斑岩则可能来源于地壳物质的部分熔融。双峰式火山岩的形成可能与上地幔玄武岩浆的底侵作用有关。裂谷演化导致的陆相火山活动持续到早二叠世晚期达到顶峰，中二叠世以后，构造环境由拉伸转为挤压，裂谷演化趋于终止。该区石炭纪末-早二叠世的裂谷活动与整个天山地区晚古生代的构造演化背景具有一致性。
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| 关 键 词： | 阿吾拉勒山西段 伊犁古裂谷 双峰式火山岩 岩石地球化学 构造背景 |
| 收稿时间： | 2/4/2013 10:24:32 AM |
| 修稿时间： | 2/21/2013 4:35:37 AM |
Geochemistry Petrogenesis and Tectonic Settings of the Lower Permian Series Volcanic Rocks from Western Awulale Mountain Xinjiang |
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| ZHAO Jun,ZHANG Zuoheng,ZHANG He,LIU Min,HONG Wei and JIANG Zongsheng.Geochemistry Petrogenesis and Tectonic Settings of the Lower Permian Series Volcanic Rocks from Western Awulale Mountain Xinjiang[J].Acta Geologica Sinica,2013,87(4):525-541. |
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| Authors: | ZHAO Jun ZHANG Zuoheng ZHANG He LIU Min HONG Wei and JIANG Zongsheng |
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| Abstract: | As a important partion of the ancient Yili Rift, the western Awulale Mountain possess typical bimodal volcanic rocks(basalts-rhyolite) in the Lower Permian Series. These rocks are generally characterized with higher Na2O and Al2O3 contents, lower TiO2 content and alkali-rich. The basalts are enriched with large-ion-lithophile elements(LILE)such as Ba, K, P and light rare earth elements(LREE), depleted of high-field-strength elements (HFSE)such as Th, U, Ta and Nb. Comparatively, the other rocks are enriched with Rb, K , LREE and Th, U, Zr and Hf, depleted of Ta, Nb, Sr and Ti. The basaltic magma is derived from weak depleted mantle and possibly contaminted by lower crust. In contrast, the rhyolites are production resulted from partial melting of crust. The petrogenesis of bimodal volcanic rocks is associatied with the underplating of the basaltic magma. Mixing and materials exchanging happened between acidic magma generated from melting of lower crust and the basaltic magma. The Yili Rift is generated under extensional stresses in response to the post-orogenic stage. The rift system in western Awulale Mountain evolves to its maturity and rapidly weaken at end-stage of Early Permian because the tectonic setting is changed from extension to compression. The late Carboniferous period-early Permian period rift evolution in western Awulale Mountain is accordant with the tectonic evolution of Tianshan orogen in late Paleozoic. |
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| Keywords: | Western Awulale Mountain Ancient Yili Rift Bimodal volcanic rocks Petrology and geochemistry Tectonic setting |
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