...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >A trapped Philippine Sea plate origin for MORB from the inner slope of the Izu-Bonin trench
【24h】

A trapped Philippine Sea plate origin for MORB from the inner slope of the Izu-Bonin trench

机译：伊豆-波宁海沟内坡的MORB被困菲律宾海板块起源

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Basement outcrops sampled by submersible and dredge from the inner slope of the Izu-Bonin trench at 32 deg N and 6200-6700 m water depth have a distinct mid-ocean ridge basalt (MORB) chemistry unlike any other rocks previously sampled in the Izu-Bonin arc. They are low K tholeiites with moderate TiO_2 (0.7-1.8 wt%), extremely low Ba (1.5-7 parts per million), low Ba/LA (1.2-3) and are depleted in light rare-earth elements. These samples could represent either an accreted piece of subducting Pacific plate or a trapped remnant of Philippine Sea plate on which the Izu-Bonin arc was built. Although their major and trace element chemistry do not help to distinguish their source, the Sr, Nd and Pb isotopes clearly support a Philippine Sea plate origin. The isotopic signature of the inner trench slope samples matches that of Philippine Sea plate lavas, with ~(87)Sr/~(86)Sr = 0.70321-0.70373, ~(143)Nd/~(144)Nd = 0.513057-0.513077 and ~(206)Pb/~(204)Pb = 18.2-18.5. The samples have elevated ~(207)Pb/~(204)Pb (15.3-15.5) and ~(208)Pb/~(204)Pb (38.0-38.2) values compared to the Northern Hemisphere reference line (NHRL) and their isotopic signature is distinct from the Mesozoic Pacific MORB being subducted. These are the first samples of trapped Philippine Sea oceanic crust discovered in the Izu-Bonin-Mariana arc. They require that models for the formation of intra-oceanic are crust account for pre-existing oceanic crust and that estimates of arc magma production rates are lowered accordingly.
机译：在32°N和6200-6700 m水深处，从伊豆邦宁海沟内坡的潜水和挖泥机取样的地下露头具有独特的中洋洋脊玄武岩（MORB）化学成分，这与之前在伊豆火山岩中取样的任何其他岩石不同Bonin弧。它们是具有中等TiO_2（0.7-1.8 wt％），极低的Ba（百万分之1.5-7份），低的Ba / LA（1.2-3）的低K辉绿岩，并且贫乏轻稀土元素。这些样品可能代表一块俯冲的俯冲的太平洋板块，或是代表其上筑有伊豆-波宁弧的菲律宾海板块的残留物。尽管它们的主要和微量元素化学成分无法区分其来源，但Sr，Nd和Pb同位素显然支持菲律宾海板块的起源。内沟斜坡样品的同位素特征与菲律宾海板熔岩的同位素特征相匹配，〜（87）Sr /〜（86）Sr = 0.70321-0.70373，〜（143）Nd /〜（144）Nd = 0.513057-0.513077和〜（206）Pb /〜（204）Pb = 18.2-18.5。与北半球参考线（NHRL）和它们的参考线相比，样品的〜（207）Pb /〜（204）Pb（15.3-15.5）和〜（208）Pb /〜（204）Pb（38.0-38.2）值升高。同位素特征不同于被俯冲的中生代太平洋MORB。这些是在伊豆-波宁-马里亚纳弧线中发现的被困菲律宾海洋壳的第一批样品。他们要求海洋内部形成的模型是早已存在的海洋地壳的地壳核算，并且相应地降低了弧岩浆产量的估算。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号