• 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 >Water, iron, redox environment: effects on the wadsleyite-ringwoodite phase transition
【24h】

Water, iron, redox environment: effects on the wadsleyite-ringwoodite phase transition

机译：水，铁，氧化还原环境：对沃兹利石-林伍德石相变的影响

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

The transition zone of the Earth's upper mantle is characterized by three discontinuities in seismic wave velocity profiles. One of these at about a depth of 520 km is assigned to the transformation of wadsleyite (beta-) to ringwoodite [gamma-(Mg, Fe)(2)SiO4] (e.g., Shearer in J Geophys Res 101: 3053-3066, 1996). The exact location, width, and other properties of that discontinuity are affected by a multitude of parameters. The present study specifically focuses on the effect of water, iron content, and redox environment on the depth of the phase transition. We performed high-pressure experiments in a multi-anvil apparatus at 1200 degrees C with variation in Mg-Fe compositions (0.10 < x(Fe) < 0.24), water contents (0 < xH(2)O < 2 wt%), and the redox environment [ using different buffers: Fe/FeO (reducing), Re/ReO2 (oxidizing)]. Run products were investigated using electron microprobe and Fourier transform infrared spectroscopy to obtain the composition including the hydroxyl concentration of coexisting phases. Mossbauer (MB) spectroscopy and electron energy loss spectroscopy as well as single-crystal X-ray diffraction were applied to gain insight into the Fe3+ content and incorporation mechanisms. Under hydrous and reducing conditions, the wadsleyite-ringwoodite boundary shifts by 0.5 GPa to higher pressures accompanied by a broadening of the region of coexisting wadsleyite and ringwoodite. In contrast, under hydrous and oxidizing conditions, the two-phase field gets narrower and the shift of the two-phase field to higher pressure is amplified. Thus, the stability field of wadsleyite is extended to higher pressure, most likely due to the higher water and Fe3+ content in the wadsleyite structure compared to ringwoodite. Based on results from MB spectroscopy and single-crystal X-ray diffraction, we infer that Fe3+ in wadsleyite is incorporated as a spinelloid component and stabilizes wadsleyite to higher pressures.
机译：地球上地幔的过渡带的特征是地震波速度剖面中的三个不连续点。其中约520 km的深度被指定为将沃兹利特（beta-）转变为林铁矿[gamma-（Mg，Fe）（2）SiO4]（例如，Shearer in J Geophys Res 101：3053-3066， 1996）。该不连续性的确切位置，宽度和其他属性受众多参数影响。本研究特别关注水，铁含量和氧化还原环境对相变深度的影响。我们在1200摄氏度的多砧装置中进行了高压实验，实验中Mg-Fe成分（0.10

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