| 西秦岭下拉地超基性岩体的地球化学特征及构造意义 |
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| 引用本文： | 费一清,周贤君.西秦岭下拉地超基性岩体的地球化学特征及构造意义[J].西北地质,2012(3):48-56. |
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| 作者姓名： | 费一清 周贤君 |
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| 作者单位： | 中国科学院油气资源研究重点实验室;甘肃省地矿局第二地质矿产勘查院 |
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| 基金项目： | 国家科技重大专项(2011ZX05008-00W-X0);甘肃国土资源厅项目(1∶250000“岷县幅”地质矿产调查项目) |
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| 摘 要： | 系统研究了西秦岭下拉地超基性岩的地质与地球化学特征,结果表明:下拉地超基性岩具有低SiO2、富Mg和贫碱特点;变质原岩主要属于橄榄岩类;不同岩石类型之间微量元素及稀土元素的分布具有一定差异;下拉地岩体的原生超基性岩岩浆主要起源于上地幔,成因类型属于俯冲带地幔橄榄岩;岩浆演化过程中受到壳源物质的加入和海相碳酸盐物质的加入,造成下拉地超基性岩高Al2O3、高CaO的特殊地球化学组成特点。笔者对由于蚀变作用影响形成的地球化学特征的原因进行了初步探讨。
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| 关 键 词： | 下拉地 超基性岩 地球化学 岩浆成因 构造意义 |
Geochemical Characteristics of Xialadi Ultrabasic Intrusion of Western Qinling and Its Tectonic Significance |
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| FEI Yi-qing,ZHOU Xian-jun.Geochemical Characteristics of Xialadi Ultrabasic Intrusion of Western Qinling and Its Tectonic Significance[J].Northwestern Geology,2012(3):48-56. |
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| Authors: | FEI Yi-qing ZHOU Xian-jun |
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| Institution: | 1. Key Laboratory of Petroleum Resources Research,Institute of Geology and Geophysics,Chinese Academy of Sciences,Lanzhou 730000,China; 2. Second Institute of Geological and Mineral Exploration of Gansu Province Bureau of Geology and Mineral Resource, Lanzhou 730020,China) |
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| Abstract: | The geological and geochemical characteristics of Xialadi ultrabasic rock of western Qinling were studied systematically in this paper. The results show that the characterization of Xialadi ultrabasic rocks is low SiO2, Mg rich and alkaline poor, in which metamorphic preexisting rocks belongs to the class of peridotite. The distribution of trace elements and rare earth elements (REE) among various rock types is different. The primary magma of Xialadi ultrabasic rocks originates from upper mantle, whose genetic type belongs to the mantle peridotite of subduction zone. Materials of crustal source and marine carbonate were added to Xialadi ultrabasic magma during its evolution, which resulted in the special geochemical composition characteristics of Xialadi ultramafic rocks with high Al2O3 and CaO. In this paper, a preliminary discussion was carried out on the reasons of the differences in geochemical characteristics of Xialadi ultrabasic rocks due to the effects of alteration. |
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| Keywords: | Xialadi ultrabasic rock geochemistry magma genesis tectonic implications |
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