| 新疆中天山南缘乌瓦门地区蛇绿岩中超镁铁岩的成因:来自岩石矿物学和地球化学的证据 |
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| 引用本文： | 牛晓露 杨经绥 刘 飞 冯光英 田亚洲 张 岚,高 健,赵一珏.新疆中天山南缘乌瓦门地区蛇绿岩中超镁铁岩的成因:来自岩石矿物学和地球化学的证据[J].中国地质,2015(5):1404-1420. |
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| 作者姓名： | 牛晓露 杨经绥 刘 飞 冯光英 田亚洲 张 岚 高 健 赵一珏 |
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| 作者单位： | 1. 大陆构造与动力学国家重点实验室地幔研究中心，中国地质科学院地质研究所，北京 100037；2. 中国地质大学 (北京) 地球科学与资源学院，北京100083 |
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| 基金项目： | 国土资源部公益性行业科研专项经费项目（201011034）、国家自然科学基金重点项目NSFC（40930313）、国家自然科学基金创新群体项目NSFC（40921001）、国家自然科学青年基金项目NSFC（41302038）、国家行业专项（SinoProbe-05-02）和中国地质调查局工作项目（12120115027201）联合资助。 |
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| 摘 要： | 本文对新疆中天山南缘乌瓦门蛇绿混杂岩中的超镁铁岩进行了岩石矿物学和地球化学研究,对其成因和形成环境进行限定。乌瓦门蛇绿混杂岩中的超镁铁岩为蛇纹石化二辉橄榄岩,由橄榄石(Fo=89.1~90.6)、斜方辉石(Wo0.4-2.4En87.2~90.7Fs8.9-10.9;Mg#=89.0~91.0)、单斜辉石(Wo49.1-51.3En16.0~48.4Fs0.9-4.3;Mg#=90.2~92.1)和尖晶石(Mg#=71.8~77.5;Cr#=9.3~13.4)组成。主量元素组成上,以低Mg O(37.74%~41.34%)、高Al2O3(2.58%~3.39%)、高Ca O(2.23%~3.68%)和高Ti O2(0.05%~0.11%)为特征。微量元素上,亏损稀土元素(REE总量为1.73×10-6~4.63×10-6),亏损不相容元素(如,Rb=0.4×10-6~1.39×10-6,Zr=0.73×10-6~3.28×10-6,Hf=0.04×10-6~0.11×10-6),富集相容元素(如,Cr=2516×10-6~2793×10-6,Co=84.6×10-6~119×10-6,Ni=1641×10-6~2261×10-6)。矿物学和地球化学特征一致指示,乌瓦门蛇绿混杂岩中的超镁铁岩为经历过低程度(5%~10%)部分熔融作用的残余地幔橄榄岩,形成于洋中脊环境,是MOR型蛇绿岩中的地幔橄榄岩。
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| 关 键 词： | 残余地幔橄榄岩 超镁铁岩 蛇绿岩 乌瓦门 天山 新疆 |
Mineralogical and geochemical constraints on the origin of the ultramafic rocks from Wuwamen ophiolite on the southern margin of Middle Tianshan Mountains, Xinjiang |
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| NIU Xiao-lu,YANG Jing-sui,LIU Fei,FENG Guang-ying,TIAN Ya-zhou,ZHANG Lan,GAO Jian,Zhao Yi-jue.Mineralogical and geochemical constraints on the origin of the ultramafic rocks from Wuwamen ophiolite on the southern margin of Middle Tianshan Mountains, Xinjiang[J].Chinese Geology,2015(5):1404-1420. |
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| Authors: | NIU Xiao-lu YANG Jing-sui LIU Fei FENG Guang-ying TIAN Ya-zhou ZHANG Lan GAO Jian Zhao Yi-jue |
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| Institution: | 1.CARMA, State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; 2. School of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083, China |
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| Abstract: | Abstract: The Wuwamen ophiolite is located on the southern margin of Middle Tianshan Mountains, Xinjiang. In this paper, petrology, mineralogy and geochemistry of the ultramafic rocks from Wuwamen ophiolite were studied to constrain their origin and tectonic setting. The ultramafic rocks from Wuwamen ophiolite are serpentinized lherzolites composed of olivine (Fo=89.1-90.6), orthopyroxene (Wo0.4-2.4En87.2~90.7Fs8.9-10.9; Mg#=89.0-91.0), clinopyroxene (Wo49.1-51.3En16.0~48.4Fs0.9-4.3; Mg#=90.2-92.1) and spinel (Mg#=71.8-77.5; Cr#=9.3-13.4). They are characterized by relatively lower content of MgO (37.74%-41.34%), and higher content of Al2O3 (2.58%-3.39%), CaO (2.23%-3.68%) and TiO2 (0.05%-0.11%). The ultramafic rocks are also depleted in rare earth elements (REE; total REE = 1.73×10?6-4.63×10?6) and incompatible elements (e.g., Rb=0.4×10?6-1.39×10?6, Zr=0.73×10?6-3.28×10?6, Hf=0.04×10?6-0.11×10?6), and enriched in compatible elements (e.g., Cr=2516×10?6-2793×10?6, Co=84.6×10?6-119×10?6, Ni=1641×10?6-2261×10?6). These data indicate that the ultramafic rocks from Wuwamen ophiolite are residues of mantle rocks after low degrees (ca. 5%-10%) of partial melting in a Mid-Ocean-Ridge (MOR) environment. |
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| Keywords: | residual mantle rocks ultramafic rocks ophiolite Wuwamen Tianshan Mountains Xinjiang |
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