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首页> 外文学位 >Solar Wind Sodium and Potassium Abundance Analysis in Genesis Diamond-on-Silicon and Silicon Bulk Solar Wind Collectors, and How Hydration Affects the Microtexture of Olivine Phase Transformation at 18 GPa.
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Solar Wind Sodium and Potassium Abundance Analysis in Genesis Diamond-on-Silicon and Silicon Bulk Solar Wind Collectors, and How Hydration Affects the Microtexture of Olivine Phase Transformation at 18 GPa.

机译：硅基金刚石和硅基散装太阳能集热器中太阳风中钠和钾的丰度分析，以及水合如何影响18 GPa橄榄石相变的微观组织。

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摘要

The present work covers two distinct microanalytical studies that address issues in planetary materials: (1) Genesis Na and K solar wind (SW) measurements, and (2) the effect of water on high-pressure olivine phase transformations.;NASA's Genesis mission collected SW samples for terrestrial analysis to create a baseline of solar chemical abundances based on direct measurement of solar material. Traditionally, solar abundances are estimated using spectroscopic or meteoritic data. This study measured bulk SW Na and K in two different Genesis SW collector materials (diamond-like carbon (DlC) and silicon) for comparison with these other solar references. Novel techniques were developed for Genesis DlC analysis. Solar wind Na fluence measurements derived from backside depth profiling are generally lower in DlC than Si, despite the use of internal standards. Nevertheless, relative to Mg, the average SW Na and K abundances measured in Genesis wafers are in agreement with solar photospheric and CI chondrite abundances, and with other SW elements with low first ionization potential (within error). The average Genesis SW Na and K fluences are 1.01e11 (+9e09, -2e10) atoms/cm2 and 5.1e09 (+8e08, -8e08) atoms/cm 2, respectively. The errors reflect average systematic errors. Results have implications for (1) SW formation models, (2) cosmochemistry based on solar material rather than photospheric measurements or meteorites, and (3) the accurate measurement of solar wind ion abundances in Genesis collectors, particularly DlC and Si.;Deep focus earthquakes have been attributed to rapid transformation of metastable olivine within the mantle transition zone (MTZ). However, the presence of H2O acts to overcome metastability, promoting phase transformation in olivine, so olivine must be relatively anhydrous (<75 ppmw) to remain metastable to depth. A microtextural analysis of olivine phase transformation products was conducted to test the feasibility for subducting olivine to persist metastably to the MTZ. Transformation (as intracrystalline or rim nucleation) shifts from ringwoodite to ringwoodite-wadsleyite nucleation with decreasing H2O content within olivine grains. To provide accurate predictions for olivine metastability at depth, olivine transformation models must reflect how changing H2O distributions lead to complex changes in strain and reaction rates within different parts of a transforming olivine grain.
机译：本工作涵盖两个不同的微观分析研究，这些研究针对行星材料的问题：（1）创世纪Na和K太阳风（SW）的测量，以及（2）水对高压橄榄石相变的影响。; NASA的创世纪任务收集了SW样品用于地面分析，可基于直接测量太阳能材料来创建太阳能化学丰度的基线。传统上，使用光谱或气象数据来估计太阳丰度。这项研究测量了两种不同创世纪SW收集器材料（类金刚石碳（DlC）和硅）中的块状SW Na和K，以与其他太阳能参考材料进行比较。开发了用于Genesis Dlc分析的新技术。尽管使用了内部标准，但在DlC中，由背面深度剖析得出的太阳风Na注量测量值通常低于Si。然而，相对于Mg，在Genesis晶圆中测得的平均SW Na和K丰度与太阳光球和CI球粒陨石的丰度以及其他具有较低第一电离势的SW元素（误差内）一致。 Genesis SW Na和K的平均通量分别为1.01e11（+ 9e09，-2e10）原子/ cm2和5.1e09（+ 8e08，-8e08）原子/ cm 2。误差反映平均系统误差。结果对（1）SW形成模型，（2）基于太阳材料而不是光球测量或陨石的宇宙化学以及（3）准确测量创世记收集器中太阳风离子丰度（特别是DlC和Si）具有深远意义。地震归因于地幔过渡带（MTZ）内亚稳橄榄石的快速转变。但是，H2O的存在是为了克服亚稳性，促进橄榄石中的相变，因此橄榄石必须相对无水（<75 ppmw）才能保持亚稳至深度。进行了橄榄石相变产物的微观结构分析，以检验将橄榄石俯冲到MTZ的可能性。随着橄榄石颗粒中H2O含量的降低，转变（作为晶内或边缘核形）从菱铁矿转变为菱铁矿-瓦兹利岩成核。为了提供深度的橄榄石亚稳性的准确预测，橄榄石转化模型必须反映不断变化的H2O分布如何导致转化橄榄石晶粒不同部分中应变和反应速率的复杂变化。

著录项

  • 作者

    Rieck, Karen Dianne.;

  • 作者单位

    Arizona State University.;

  • 授予单位 Arizona State University.;
  • 学科 Geochemistry.;Mineralogy.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 297 p.
  • 总页数 297
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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