• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Effects of hydration on equation of state (EOS) of Mg2SiO4(forsterite) phases in the upper mantle & transition zone by single-crystal x-ray diffraction.
【24h】

Effects of hydration on equation of state (EOS) of Mg2SiO4(forsterite) phases in the upper mantle & transition zone by single-crystal x-ray diffraction.

机译：单晶X射线衍射分析水合对上地幔及过渡带Mg2SiO4（镁橄榄石）相状​​态方程（EOS）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

Olivine, wadsleyite and ringwoodite are the three phases of Mg2 SiO4, which dominate 60 ∼ 70 vol. % of mineralogy in the upper mantle and transition zone. Water may be transported to the transition zone or deeper in the forms of dense hydrous magnesium silicates, and also by hydrogen incorporated into nominally anhydrous silicate phases. Wadsleyite and ringwoodite in transition zone could contain up to ∼3 wt% H2 O, and these small amounts of H2O can have significant effects on the physical properties and seismological velocities. Single-crystal XRDs were conducted to refine unit-cell parameters and internal structures at temperatures and pressures to study effects of hydration on equation of state. Hydration significantly increases thermal expansion and compressibility. At Argonne National Laboratory, APS, we measured the compressibility of hydrous wadsleyite (2.8(5) wt% H2O) and hydrous ringwoodite (2.5(3) wt% H2O), and the 3rd-order B-M EOS fits the results: KT0 = 137(5) GPa, K&feet; = 4.6(3) for hydrous wadsleyite; KT0 = 160(2) GPa, K' = 6.2(3) for hydrous ringwoodite. For both wadsleyite and ringwoodite, one wt% increasing in water content would decrease the isothermal modulus (KT0) by about 12 GPa, while increase K'. Dehydration phenomena of hydrous wadsleyite were observed at about 650 K, and after dehydration, M2 -- O1 and M3 -- O1 bonds' lengths decreased by 3 % and 2.5 %, respectively. Irreversible expansion phenomena were observed at high temperatures for hydrous ringwoodite samples: a small mount of H+ cations in Mg sites appear to transfer to Si sites without changing the spinel structure of ringwoodite, and the substituted Si4+ cations move to the normally vacant octahedral site at (½ , ½, 0). SiO4 tetrahedral volume for hydrous ringwoodite increases significantly during irreversible expansion, but does not change for hydrous wadsleyite during dehydration. In addition, thermal expansion study of aragonite-group carbonate indicate that aragonite, strontianite and witherite have very similar &agr;0(V) values, whereas that of cerussite is significant larger.
机译：橄榄石，沃兹利特石和林伍德石是Mg2 SiO4的三相，占60至70 vol。上地幔和过渡带的矿物学百分比。水可以以致密的含水硅酸镁的形式，也可以通过将氢掺入标称无水硅酸盐相中的形式，输送到过渡区或更深处。过渡带中的辉石岩和菱铁矿可能含有约3 wt％的H2 O，而这些少量的H2O会对物理性质和地震速度产生重大影响。进行了单晶XRD，以在温度和压力下细化晶胞参数和内部结构，以研究水合对状态方程的影响。水合显着增加了热膨胀和可压缩性。在阿贡国家实验室（APS）处，我们测量了含水沃兹利石（2.8（5）wt％H2O）和含水水杨木石（2.5（3）wt％H2O）的可压缩性，并且三阶BM EOS拟合结果：KT0 = 137 （5）GPa，K＆feet； = 4.6（3）（对于含水辉石）；含水林木KT0 = 160（2）GPa，K'= 6.2（3）。对于沃兹利特石和林伍德石而言，水含量增加1 wt％会使等温模量（KT0）降低约12 GPa，而K'升高。在约650 K处观察到含水辉石矿的脱水现象，脱水后，M2-O1和M3-O1键的长度分别减少了3％和2.5％。含水林木样品在高温下观察到不可逆的膨胀现象：在Mg位点上少量的H +阳离子似乎转移到Si位，而不会改变林板晶的尖晶石结构，并且被取代的Si4 +阳离子移到（）处的正常空八面体位½，½，0）。含水林木石的SiO4四面体体积在不可逆膨胀过程中会显着增加，但在脱水过程中对于含水辉石矿则不会改变。另外，文石族碳酸盐的热膨胀研究表明文石，锶锶矿和堇青石具有非常相似的α0（V）值，而铜铁矿的值显着更大。

著录项

  • 作者

    Ye, Yu.;

  • 作者单位

    University of Colorado at Boulder.;

  • 授予单位 University of Colorado at Boulder.;
  • 学科 Geology.;Mineralogy.;Geophysics.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 163 p.
  • 总页数 163
  • 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
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