...
  • 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 >Refertilization of mantle peridotite in embryonic ocean basins: trace element and Nd isotopic evidence and implications for crust–mantle relationships
【24h】

Refertilization of mantle peridotite in embryonic ocean basins: trace element and Nd isotopic evidence and implications for crust–mantle relationships

机译：胚胎洋盆中地幔橄榄岩的蚀变：痕量元素和Nd同位素证据及其对地幔关系的影响

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

Many mantle peridotites exhumed along ancient and present-day magma-poor passive continental margins, along (ultra-) slow spreading ridges and fracture zones are plagioclase-bearing and generally too fertile to be the residue of partial melting processes alone. Likewise, the associated gabbroic and basaltic rocks are not a priori genetically linked to the underlying mantle rocks. Trace element and Nd isotopic studies in the eastern Central Alps peridotites in eastern Switzerland and northern Italy provide evidence for near-fractional melting and depletion at high pressure in Permian time followed by refertilization of subcontinental mantle by ascending melts at low pressure in Jurassic time. These results suggest regional-scale modification of ancient subcontinental mantle by melt infiltration and melt–rock reaction during incipient opening of oceanic basins. The similar Nd isotopic composition of plagioclase peridotite (Nd_(160): 7.4–10.6) and associated mafic crust (Nd_(160): 7.3–9.6) indicates that the liquids, which reacted with the peridotites derived from similar N-MORB type mantle sources. Plagioclase peridotites in magma-poor passive margins may predominantly form as a consequence of diffuse porous flow of melt in the thermal boundary layer above an upwelling asthenosphere and probably represent modified ancient subcontinental mantle. Thus, plagioclase peridotites exhumed in passive margins and possibly in (ultra-) slow spreading ridges may represent magma-poor periods where liquids stagnate in the thermal boundary layer and react with the surrounding peridotites. Once the effects of conductive heat loss dominate over advection of heat from below, diffuse porous flow of melt becomes less important and might be replaced by the formation of gabbro bodies.
机译：许多地幔橄榄岩沿着古老的和当今的岩浆稀少的被动大陆边缘，沿着（超）缓慢扩散的山脊和断裂带被挖出，它们是斜长石，通常肥沃而不能单独成为部分熔融过程的残余物。同样，相关的辉长岩和玄武岩也不是与下地幔岩先天遗传相关的。在瑞士东部和意大利北部中部阿尔卑斯山东部橄榄岩中的微量元素和Nd同位素研究提供了证据，证明了在二叠纪高压下近乎部分熔融和耗竭，随后在侏罗纪低压下通过升高熔体使次大陆幔转化。这些结果表明，在大洋盆地初期开放期间，熔岩渗透和熔岩反应对古代次大陆幔进行了区域范围的改造。斜长石橄榄岩（Nd_（160）：7.4–10.6）和相关的镁铁质壳（Nd_（160）：7.3–9.6）具有相似的Nd同位素组成，表明与与类似N-MORB型地幔衍生的橄榄岩反应的液体资料来源。岩浆较差的被动缘中的斜长岩橄榄岩可能主要是由于上升流软流层上方热边界层中熔体的弥散多孔流动而形成的，并且可能代表了古老的次大陆幔。因此，斜长石橄榄石在被动边缘和可能的（超）缓慢扩散的脊中发掘可能代表了岩浆贫乏时期，其中液体在热边界层中停滞并与周围的橄榄石反应。一旦传导性热损失的影响超过了来自下方的热对流，熔体的分散多孔流就变得不那么重要了，并可能由辉长岩体的形成所取代。

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