古地幔柱作用“遗迹”的深部地球物理探测——以峨眉山大火成岩省为例

发布时间：2018-03-06 22:20

本文选题：古地幔柱　切入点：峨眉山大火成岩省　出处：《矿物岩石地球化学通报》2017年03期 　论文类型：期刊论文

【摘要】：大火成岩省成因是国际地学界的研究热点,涉及地球内部运行机制和过程、资源和生物环境效应等多个地学前沿研究领域。峨眉山大火成岩省不仅是中国境内第一个获得国际学术界广泛认可的大火成岩省,也是全球范围内研究程度最高的大陆溢流玄武岩省之一。前人基于沉积地层学、岩石地球化学等系列证据提出了该大火成岩省的"地幔柱头熔融"成因模型。深部是否存在"地幔柱头熔融"假说所预示的大规模岩浆作用"遗迹",有待地球物理探测的进一步检验。地球物理方法是探测现代地幔柱的常用手段。本项研究集成利用人工源地震、天然源宽频带地震探测,以及密集重力/地磁剖面测量等综合地球物理手段探测"古地幔柱"作用,在峨眉山大火成岩省研究中取得了系列成果,其研究思路与方法对其他古地幔柱作用"遗迹"的识别具有重要的借鉴意义。通过几何结构-物性结构-动力学属性参数之间的联合约束,以及与地球化学、地质学研究成果的有机结合,可靠地揭示出与古地幔柱作用有关的大规模岩浆活动导致的地壳结构和组分变化以及深浅响应过程等,显示了综合地球物理方法、不同学科交叉融合在重建古老重大地质事件深部过程方面的巨大潜力。大规模岩浆作用"底侵"位置的确定、"透明"上地壳特征的发现等,对于该区未来的深部找矿具有重要的指导意义。
[Abstract]:The Genesis of the Great igneous Province is a hot research topic in the international geoscience field, which involves the operation mechanism and process of the earth's interior. Emeishan great igneous rock province is not only the first major igneous rock province in China that has been widely recognized by the international academic community, It is also one of the most studied continental basalt provinces in the world. A series of evidences, such as petrogeochemistry, have been put forward for the "mantle plume melting" genetic model of this igneous province. Whether there is a large-scale magmatism "vestige" in the deep part of the earth, as predicted by the hypothesis of "mantle plume melting", remains to be found in the earth. Geophysical methods are commonly used in the detection of modern mantle plumes. This study integrates the use of artificial earthquakes, A series of achievements have been made in the study of Emeishan great igneous rock province, such as wide band seismic exploration of natural sources and integrated geophysical methods such as dense gravity / geomagnetic profiling to detect "paleomembrane plume". Its research ideas and methods are of great significance for the identification of other paleo-mantle plume "relics". Through the joint constraints between geometric structure-physical structure-dynamic attribute parameters, and geochemistry, the method can be used as a reference for the identification of other paleo-mantle plume "relics". The organic combination of geological research results reliably reveals the crustal structure and composition changes and the deep and shallow response processes caused by large-scale magmatic activities related to paleomembrante plume, and shows a comprehensive geophysical method. The great potential of different disciplines in reconstructing the deep process of ancient major geological events, the determination of the location of large-scale magmatism, the discovery of "transparent" features of the upper crust, etc. It has important guiding significance for the future deep prospecting in this area.
【作者单位】：中国科学院地质与地球物理研究所岩石圈演化国家重点实验室;中国科学院大学;中国科学院广州地球化学研究所同位素地球化学国家重点实验室;桂林理工大学地球科学学院;
【基金】：国家重点基础研究发展计划项目(2011CB808904) 中国科学院战略性先导科技(B类)专项(XDB18000000) 国家自然科学基金项目(41374063)
【分类号】：P542.5

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