| N-MORB和E-MORB数据挖掘——玄武岩判别图及洋中脊源区地幔性质的讨论 |
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| 引用本文： | 王金荣,陈万峰,张旗,焦守涛,杨婧,潘振杰,王淑华.N-MORB和E-MORB数据挖掘——玄武岩判别图及洋中脊源区地幔性质的讨论[J].岩石学报,2017,33(3):993-1005. |
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| 作者姓名： | 王金荣 陈万峰 张旗 焦守涛 杨婧 潘振杰 王淑华 |
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| 作者单位： | 兰州大学地质科学与矿产资源学院, 甘肃省西部矿产资源重点实验室, 兰州 730000,兰州大学地质科学与矿产资源学院, 甘肃省西部矿产资源重点实验室, 兰州 730000,中国科学院地质与地球物理研究所, 北京 100029,中国科学院地质与地球物理研究所, 北京 100029,兰州大学地质科学与矿产资源学院, 甘肃省西部矿产资源重点实验室, 兰州 730000,兰州大学地质科学与矿产资源学院, 甘肃省西部矿产资源重点实验室, 兰州 730000,兰州大学地质科学与矿产资源学院, 甘肃省西部矿产资源重点实验室, 兰州 730000 |
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| 基金项目： | 本文受中央高校基本科研业务费项目（Lzu-Jbky-2012-128）资助. |
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| 摘 要： | MORB分为N-MORB和E-MORB,二者的区分通常是以LREE亏损和富集为标志。玄武岩的基本理论主要是在MORB研究成果的基础上建立起来的。通常认为,N-MORB和OIB是两个独立的端元,E-MORB是N-MORB与OIB不同程度混合形成的。在20世纪70~80年代,玄武岩构造环境判别图的建立极大促进了玄武岩在地球动力学及大地构造背景研究的进展,其方法应用持续盛行了几十年。然而,国外学者现在已逐渐淡化玄武岩判别图解的应用,但在中国仍有方兴未艾之势。本文利用Pet DB数据库5万多个MORB数据的投图表明,全体样品投图的效果显然比抽样和典型样品得出的结果更扎实可靠,许多原先被广泛应用的主量、微量元素判别图无论从实践上还是理论上均存在一些问题。本文的研究结果进一步表明,MORB样品既有LREE亏损的,又有富集的,但亏损和富集程度与早先定义的差异较大,揭示了洋脊下地幔不均一性要比早先认识的更为复杂,成分范围变化更大,仅少数是强烈亏损的,部分可能是相当富集,甚至可以与OIB源区相类比;玄武岩构造环境判别图需要重新审视,基于岩浆成因机理的多维度、高置信度的判别体系有待于建立。
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| 关 键 词： | MORB N-MORB E-MORB 玄武岩 判别图 数据挖掘 |
| 收稿时间： | 2016/3/5 0:00:00 |
| 修稿时间： | 2016/10/15 0:00:00 |
Preliminary research on data mining of N-MORB and E-MORB: Discussion on method of the basalt discrimination diagrams and the character of MORB's mantle source |
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| WANG JinRong,CHEN WanFeng,ZHANG Qi,JIAO ShouTao,YANG Jing,PAN ZhenJie and WANG ShuHua.Preliminary research on data mining of N-MORB and E-MORB: Discussion on method of the basalt discrimination diagrams and the character of MORB''s mantle source[J].Acta Petrologica Sinica,2017,33(3):993-1005. |
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| Authors: | WANG JinRong CHEN WanFeng ZHANG Qi JIAO ShouTao YANG Jing PAN ZhenJie and WANG ShuHua |
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| Institution: | Key Laboratory of Mineral Resources in Western China(Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, China,Key Laboratory of Mineral Resources in Western China(Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, China,Institute of Geology and Geophysics, China Academy of Sciences, Beijing 100029, China,Institute of Geology and Geophysics, China Academy of Sciences, Beijing 100029, China,Key Laboratory of Mineral Resources in Western China(Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, China,Key Laboratory of Mineral Resources in Western China(Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, China and Key Laboratory of Mineral Resources in Western China(Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, China |
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| Abstract: | MORB can be divided into N-MORB and E-MORB, N-MORB is LREE depleted and E-MORB is enriched. Studies on MORB have greatly boosted the fundamental theories of basalts. N-MORB and OIB are generally believed to be two separate end members, and E-MORB is mixed by N-MORB and OIB in varying degrees. The diagrams for discriminating tectonic settings of basalts were established during the 1970s and 1980s, which are tremendous progress for analyzing earth dynamics and tectonic background of basalts and has thrived for decades especially in China. We have compiled more than 50000 MORB data in PetDB database for tectonic setting discrimination diagrams. The plotting diagrams applying whole samples exhibit more accurate and reliable results than that of using representative samples. Therefore, previous discrimination diagrams of major and trace elements require reexamination. Our study indicates that MORB can be either LREE depleted or enriched, and the degree of depletion or enrichment is in large difference from previous definition, which reflect that the mantle beneath ocean ridge is more heterogeneous in composition than previous understanding. In general, our study provides new, different insights to basalts, and we propose multi-dimension, high-confidence level discrimination system to be established for more research on the origin of magmas. |
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| Keywords: | MORB N-MORB E-MORB Basalt Discrimination diagram Data mining |
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