The study of the materials of the lower mantle by a laser heated diamond anvil cell and analytical electron microscopy

用激光加热金刚石砧室和分析电子显微镜研究下地幔的材料

基本信息

批准号：
12304030
负责人：
FUJINO Kiyoshi
金额：
$ 28.56万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

In this study, the YLF laser-heated diamond anvil cell (DAC) experiments at up to 100 GPa and 3000 K and analytical transmission electron microscopy (ATEM) using the ultrathin foils prepared by ultramicrotomy were developed. By the combined method of a laser-heated DAC, synchrotron X-ray diffraction and ATEM, the following results were obtained.1) High pressure syntheses of CaMgSi_2O_6-CaFeSi_2O_6 pyroxene at 30-80 Gpa and 1700-2200 K and analyses of the samples revealed that the Ca solubility in MgSiO_3 perovskite was about 1-2 mole % at 30 Gpa in the CaMgSi_2O_6 end and does not seem to change with increasing the Fe content or pressure, while the Mg solubility in CaSiO_3 perovskite was about 4 mole % at 30 Gpa in the CaMgSi_2O_6 end but the (Mg,Fe) solubility in CaSiO_3 perovskite significantly increased up to 20-30 mole % with increasing the Fe content and pressure.2) High pressure syntheses of (Mg,Fe)SiO_3-Al_2O_3 gel at 30-60 GPa and 1800-2000 K and analyses of the samples showed that the Fe solubility in (Mg,Fe)SiO_3 perovskite increased with increasing the Al content in perovskite, indicating the formation of the endmember Fe^<3+>Al^<3+>O_3 in perovskite.3) High pressure syntheses of CaSiO_3-CaTiO_3 glass at 30 Gpa and 1800 K and analyses of the samples showed that the Ti substitution for Si in CaSiO_3 perovakite produced doubling of a unit cell axis, resulting in a double perovskite-like structure in the intermediate composition of this system. This structure is face-centered cubic at high pressure and high temperature, but it inverts to a lower symmetry structure during cooling.

在这项研究中，开发了在高达 100 GPa 和 3000 K 下的 YLF 激光加热金刚石砧室 (DAC) 实验以及使用超薄切片制备的超薄箔的分析透射电子显微镜 (ATEM)。采用激光加热DAC、同步加速器X射线衍射和ATEM相结合的方法，得到了以下结果：1)CaMgSi_2O_6-CaFeSi_2O_6辉石在30-80 Gpa、1700-2200 K下的高压合成及样品分析结果表明，在 30 Gpa 条件下，Ca 在 MgSiO_3 钙钛矿中的溶解度约为 1-2 摩尔% CaMgSi_2O_6 端似乎不随 Fe 含量或压力的增加而变化，而在 CaMgSi_2O_6 端，CaSiO_3 钙钛矿中 Mg 的溶解度在 30 Gpa 下约为 4 摩尔%，但 CaSiO_3 钙钛矿中的 (Mg,Fe) 溶解度显着增加至随着 Fe 含量和压力的增加，摩尔百分比为 20-30 %。 2) 高压合成(Mg,Fe)SiO_3-Al_2O_3在30-60 GPa和1800-2000 K下的凝胶以及对样品的分析表明，随着钙钛矿中Al含量的增加，Fe在(Mg,Fe)SiO_3钙钛矿中的溶解度增加，这表明形成了钙钛矿中端元Fe^<3+>Al^<3+>O_3。3)CaSiO_3-CaTiO_3玻璃的高压合成在 30 Gpa 和 1800 K 下进行的测试以及对样品的分析表明，CaSiO_3 钙钛矿中的 Ti 取代 Si 导致晶胞轴加倍，从而在该体系的中间组合物中产生双钙钛矿结构。这种结构在高压和高温下是面心立方的，但在冷却过程中会转变为较低对称性的结构。