洋岛和洋底高原玄武岩数据挖掘:地球化学特征及其与MORB的对比

发布时间：2018-03-06 20:23

本文选题：OIB　切入点：OPB　出处：《地质学报》2017年11期 　论文类型：期刊论文

【摘要】：本文集合了GEOROC和PetDB两个数据库的资料,对全球洋岛玄武岩(Ocean Island Basalt,OIB)和洋底高原玄武岩(Ocean Plateau Basalt,OPB)数据进行分析研究。OIB和OPB是板内岩浆活动的产物,其形成一般与地幔柱(热点)有关。OPB通常指示地幔柱的头部,温度相对较低;OIB代表地幔柱的尾部,温度较高。我们对OIB的数据研究表明,OIB中的不相容元素并非像先前认为的那么富集,在构造判别图中,OIB和洋中脊玄武岩(Mid Ocean Ridge Basalt,MORB)有很大一部分是重叠的,揭示OIB源区既有强烈富集不相容元素的,也有明显亏损的,甚至还有强烈亏损类似岛弧玄武岩(Island Arc Basalt,IAB)的。OPB是指发育在海洋和大陆边缘的来自地幔的巨量玄武岩,虽然与OIB同属于板内环境,但OPB的地球化学性质更接近富集型洋中脊玄武岩(Enrich Mid Ocean Ridge Basalt,E-MORB),可能具有OIB和MORB之间过渡的特征。研究表明,OIB和OPB的源区除了来自下地幔以外(地幔柱),部分可能来自上地幔,有些还可能与板块消减带物质的再循环作用有关。因此,OIB和OPB的成因不可能只用地幔柱一种模式予以解释,还应当考虑板块活动中其他因素(洋壳再循环、古老陆壳再循环、消减带物质以及水的加入,部分熔融程度、岩浆混合作用、不同地幔端元混合等)的影响。
[Abstract]:In this paper, the data of GEOROC and PetDB are collected, and the data of global oceanic island basaltic basaltic Island (OIBB) and ocean Plateau basalt#en0# (OPBB) are analyzed. OIB and OPB are the products of intraplate magmatic activity. OPB usually indicates the head of the mantle plume, and the relatively low temperature of OIB represents the tail of the mantle plume. Our data on OIB show that the incompatible elements are not as enriched as previously thought, and there is a great deal of overlap between OIB and Mid Ocean Ridge basaltMORBs in the tectonic discriminant diagram. It is revealed that the OIB source region has both strong enrichment of incompatible elements and significant depletion, and even a strong depletion similar to that of Island Arc basaltIab), which refers to a large amount of mantle basalts developed in the ocean and continental margins. Although it belongs to the same board environment as OIB, However, the geochemical properties of OPB are more similar to those of the enriched Mid Ocean Ridge basaltl E-MORBN, which may be characterized by the transition between OIB and MORB. The results show that the source regions of OPB and OPB are derived from the lower mantle (mantle plume, some of them may come from the upper mantle). Some may also be related to the recycling of subduction zone material. Therefore, the origin of OIB and OPB cannot be explained by a single mantle plume model, and other factors in plate activity (ocean crust recycling, ancient continental crust recycling) should also be taken into account. The influence of subtractive zone material and water, partial melting degree, magmatic mixing, and different mantle end element mixing, etc.
【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(兰州大学);中国科学院地质与地球物理研究所;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;北京矿产地质研究所;
【基金】：中央高校基本科研业务费项目(编号Lzu-Jbky-2012-128)资助成果
【分类号】：P736

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