Trace-element characteristics of east-west mantle geochemical hemispheres
Trace-element characteristics of east-west mantle geochemical hemispheres
复制标题
东西地幔地球化学半球的微量元素特征
DOI：
10.1016/j.crte.2018.09.007
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发表时间：
2019
影响因子：
1.4
通讯作者：
and Satoru Haraguchi
中科院分区：
文献类型：
--
作者：
Hikaru Iwamori;Hitomi Nakamura;Masaki Yoshida;Takashi Nakagawa;Kenta Ueki;Atsushi Nakao;Tatsuji Nishizawa;and Satoru Haraguchi
最近对大洋、弧和大陆玄武岩同位素组成的统计分析表明，地幔大致分为东半球和西半球。本研究旨在利用痕量元素浓度来表征同位素定义的东西地球化学半球。除同位素比 87Sr/86Sr、143Nd/144Nd、206Pb/204Pb、207Pb/204Pb 和 208Pb/204Pb 外，玄武岩数据主要选自 GEOROC 和 PetDB 数据库。总共使用了4787个样品来研究全球地球化学变化。结果表明，广泛的微量元素变化大致可以通过熔体交代和流体交代地幔源的熔化来解释。从玄武岩推断，东半球俯冲板块产生的流体成分比西半球多。这些特征支持了这样的假设：向超大陆的集中俯冲创造了地幔地球化学半球。
Recent statistical analyses on the isotopic compositions of oceanic, arc, and continental basalts have revealed that the Earth's mantle is broadly divided into eastern and western hemispheres. The present study aimed to characterize the isotopically defined east–west geochemical hemispheres using trace-element concentrations. Basalt data with Rb, Sr, Nd, Sm, Pb, Th, and U in addition to the isotopic ratios87Sr/86Sr,143Nd/144Nd,206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb were selected mostly from the GEOROC and PetDB databases. A total of 4787 samples were used to investigate the global geochemical variations. The results show that the wide trace-element variations are broadly explained by the melting of melt-metasomatized and fluid-metasomatized mantle sources. The larger amount of the fluid component derived from subducted plates in the eastern hemisphere than that in the western hemisphere is inferred from the basalts. These characteristics support the hypothesis that focused subduction towards the supercontinent created the mantle geochemical hemispheres.