Element partitioning between minearls and silicate melt under high pressure and its implications for the evolution of the terrestrial planets

高压下矿物和硅酸盐熔体之间的元素分配及其对类地行星演化的影响

• 批准号: 10640470
• 负责人: SUZUKI Toshihiro
• 金额: $ 2.05万
• 依托单位: Gakushuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640470/
• 关键词: Element partitioning; High Pressure; Garnet; Silicate melt; Majorite; Silicate-perovskite

High pressure melting experiments on primitive mantle composition material (PM1), thoreiitic basalt (JB2) and Cr-diopside (CD1) were performed from 3 to 23.5 Gpa, and high pressure mineral/silicate melt partition coefficients, D, were measured for major and trace elements. Chemical analysis of major elements was carried out with and Electron Prove Micro Analyzer, and concentrations of trace elements were measured by Secondary Ion Mass Spectrometer. From the time study experiments of PM1 at 15GPa, it was found that at least one hour is required to achieve equilibrium condition between majorite and coexisting silicate melt. In the case of PM1, D of Majorite/silicate melt and Mg-perovskite/silicate melt were measured. D of Garnet, Clino-pyroxene and Ca-perovskite/silicate melt were also measured by using JB2 and CD1.In most of the observed high pressure minerals, D-value was remarkably decreased when the ionic radius of the elements become larger than 90 pm.Therefore, the elements whose ionic radius are larger than 90 pm will concentrate in silicate melt. However, Ca-perovskite/silicate melt system showed different partitioning behavior: Ca-perovskite can accommodate the elements whose ionic radius are 90-110 pm, and the elements with ionic radius of 60 - 80 pm are concentrated in silicate melt. It was also observed that DィイD2NaィエD2. Was obviously increased with increase in pressure. Although this behavior of DィイD2NaィエD2. May be explained by substitution process, this observation can be explained by relative shrinkage of NaィイD1+ィエD1 ion. If NaィイD1+ィエD1 relatively decrease in size for 3%, the observed change in DィイD2NaィエD2 can be explained.

在3 ~ 23.5Gpa压力范围内，对原始地幔成分物质（PM 1）、拉斑玄武岩（JB 2）和铬透辉石（CD 1）进行了高压熔融实验，测量了矿物/硅酸盐熔体的高压分配系数D。用微量元素分析仪和电子探针分析仪进行了常量元素的化学分析，用二次离子质谱仪测定了微量元素的浓度。在15 GPa压力下对PM_1的时间研究发现，在15 GPa压力下，主熔体和共存熔体达到平衡状态至少需要1小时。在PM 1的情况下，测量了镁钙钛矿/硅酸盐熔体和镁钙钛矿/硅酸盐熔体的D。用JB 2和CD 1测量了石榴石、单斜辉石和钙钛矿/硅酸盐熔体的D值。在大多数高压矿物中，当元素的离子半径大于90 μ m时，D值显著降低，因此，离子半径大于90 μ m的元素将在硅酸盐熔体中富集。而钙钛矿/硅酸盐熔体体系的分配行为不同：钙钛矿能容纳离子半径为90-110 μ m的元素，而离子半径为60 - 80 μ m的元素则集中在硅酸盐熔体中。还观察到D D2 Na D2。明显地随着压力的增加而增加。虽然这种行为的D D2 Na D2。可以用置换过程来解释，这一观察结果可以用Na + D1+ D1离子的相对收缩来解释。如果Na D1+ Na D1的大小相对减少3%，则可以解释观察到的D D2 Na D2的变化。

项目成果

Akaogi, M., T. Suzuki, R. Kojima, T. Honda, E. Ito and I. Nakai: "Enthalpy and density measurements of pressure-amorphized GeOィイD22ィエD2 quartz."Geophys. Res. Lett.. 25. 3636-3638 (1998)

Akaogi, M.、T. Suzuki、R. Kojima、T. Honda、E. Ito 和 I. Nakai：“压力非晶化地球物理学的焓和密度测量。Res. Lett。”。

Akaogi, M., Y. Hamada, T. Suzuki, M. Kobayashi and M. Okada: "High pressure transitions in the system MgAlィイD22ィエD2OィイD24ィエD2-CaAlィイD22ィエD2OィイD24ィエD2: a new hexagonal aluminous phase with implication for the lower mantle."Phys. Earth Planet. Inter. 115. 6

Akaogi, M.、Y. Hamada、T. Suzuki、M. Kobayashi 和 M. Okada：“D24D2 系统中的高压转变：一种新的六方铝相，对下地幔有影响。”Phys。 115. 6

Akaogi,M.,T.Suzuki,R.Kojima,T.Honda,E.Ito and I.Nakai: "Enthalpy and density measurements of pressure-amorphized GeO_2 quartz"Geophysical Research Letters. 25. 3636-3638 (1998)

Akaogi，M.，T.Suzuki，R.Kojima，T.Honda，E.Ito 和 I.Nakai：“压力非晶化 GeO_2 石英的焓和密度测量”地球物理研究快报。

Suzuki, T, and M. Akaogi: "Element partitioning between some mantle minerals and the coexisting silicate melt under high pressure."High Pressure - High Temperature Research: Properties of Earth and Planetary Materials Amer. Geophys. Union Monograph. 261-2

Suzuki, T, 和 M. Akaogi：“高压下某些地幔矿物与共存硅酸盐熔体之间的元素分配。”高压-高温研究：地球和行星材料的特性 Amer。

Ito, E., T. Katsura, K. Morooka, O. Ujike and T. Suzuki: "Reactions between molten iron and silicates at high pressure."High Pressure - High Temperature Research: Properties of Earth and Planetary Materials Amer. Geophys. Union Monograph. 215-225 (1998)

Ito, E.、T. Katsura、K. Morooka、O. Ujike 和 T. Suzuki：“高压下铁水和硅酸盐之间的反应。”高压-高温研究：地球和行星材料的特性 Amer。