...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Contributions to Mineralogy and Petrology >High pressure fluids in the system MgO–SiO2–H2O under upper mantle conditions
【24h】

High pressure fluids in the system MgO–SiO2–H2O under upper mantle conditions

机译：上地幔条件下MgO–SiO2 –H2 O系统中的高压流体

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

Fluids and melts have been trapped and analysed in high pressure experiments in the model mantle system MgO–SiO2–H2O at 6 to 10.5 GPa and 900 to 1,200 °C. The fluid/melt traps consisted of a diamond layer that was added to the experimental charge and was separate from the silicate phases. The recovered diamond traps were analysed by laser ablation – ICP – MS. Starting materials were synthetic mixtures of brucite, talc and silica with variable Mg/Si containing 11–31 wt% H2O. Experiments on a serpentine starting composition [Mg3Si2O5(OH)4] result in MgO/SiO2 weight ratios in the subsolidus fluids close to 1 at 6 GPa and close to 2 at 9 GPa. Melt compositions at 6 and 9 GPa have MgO/SiO2 ratios close to that of forsterite. At a single pressure the amount of dissolved silicate in the fluid increases steadily with increasing temperature up to 1,150 °C, where a sudden increase of both SiO2 and MgO is observed. This discrete step marks the solidus, which is more clearly developed at 6 than at 9 GPa. Thus, hydrous melts within the model mantle subsystem Mg2SiO4–Mg2Si2O6–H2O are chemically distinct from aqueous fluids up to at least 9 GPa, corresponding to 300 km depth. Extrapolation of the current data set implies that total convergence between fluid and melt along the solidus probably occurs at 12–13 GPa (~400 km), i.e. close to the Earth's mantle transition zone. Beneath cratons, interactions of hydrous fluids with upper mantle lithologies cause relative silica depletion (olivine enrichment) at depths greater than 200 km and silica (orthopyroxene) enrichment at shallower depths.
机译：在模型罩系统MgO–SiO2 –H2 O中，在6至10.5 GPa和900至1,200°C的高压实验中，流体和熔体已被捕集和分析。流体/熔体阱由金刚石层组成，该金刚石层被添加到实验装料中并与硅酸盐相分离。通过激光烧蚀– ICP – MS分析回收的钻石阱。起始原料是水镁石，滑石和二氧化硅的合成混合物，其中的Mg / Si含量为11-31 wt％H2 O。蛇纹石起始成分[Mg3 Si2 O5 （OH）4 ]的实验导致亚固相流体中MgO / SiO2 的重量比在1附近6 GPa，在9 GPa时接近2。 6和9 GPa的熔体成分MgO / SiO2 比接近镁橄榄石。在单一压力下，随着温度升高至1,150°C，流体中溶解的硅酸盐的量稳定增加，观察到SiO2和MgO均突然增加。此离散步骤标记了固相线，固相线在6 GPa时比在9 GPa时更清晰。因此，模型幔子系统Mg2 SiO4 –Mg2 Si2 O6 –H2 O中的含水熔体在化学上与含水流体不同至少9 GPa，对应于300 km深度。当前数据集的外推意味着，沿着固相线的流体和熔体之间的总会聚可能发生在12-13 GPa（〜400 km），即接近地球的地幔过渡带。在克拉通下方，含水流体与上地幔岩性的相互作用导致深度大于200 km的相对二氧化硅损耗（橄榄石富集）和较浅深度的二氧化硅（邻二甲苯）富集。

著录项

  • 来源
    《Contributions to Mineralogy and Petrology》 |2001年第5期|607-618|共12页
  • 作者

    R. Stalder; P. Ulmer; A. Thompson; D. Günther;

  • 作者单位

    Institut für Mineralogie und Petrographie ETH Zentrum Sonneggstrasse 5 8092 Zürich Switzerland;

    Institut für Mineralogie und Petrographie ETH Zentrum Sonneggstrasse 5 8092 Zürich Switzerland;

    Institut für Mineralogie und Petrographie ETH Zentrum Sonneggstrasse 5 8092 Zürich Switzerland;

    Laboratorium für Anorganische Chemie ETH Zentrum Universitätsstrasse 6 8092 Zürich Switzerland;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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