High pressure phase equilibria of constituent minerals of mantle and oceanic crust, and chemical heterogeneity of deep mantle

地幔和洋壳组成矿物的高压相平衡及深部地幔化学非均质性

• 批准号: 15204049
• 负责人: AKAOGI Masaki
• 金额: $ 32.36万
• 依托单位: Gakushuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15204049/
• 关键词: mantle; oceanic crust; high-pressure experiment; calorimetry; high-pressure phase equilibrium; post-spinel; perovskite; post-perovskite; エンタルピー; エントロピー; 相平衡; ポスト・ペロブスカイト; スピネル; 変型スピネル; 高圧相平衡実験; ラマン分光測定; カルシウムフェライト; 六方晶系相; 熱量測定; 格子振動モデル; mantle; oceanic crust; high-pressure experiment; calorimetry; high-pressure phase equilibrium; post-spinel; perovskite; post-perovskite; エンタルピー; エントロピー; 相平衡; ポスト・ペロブスカイト; スピネル; 変型スピネル; 高圧相平衡実験; ラマン分光測定; カルシウムフェライト; 六方晶系相; 熱量測定; 格子振動モデル

1. High-pressure stability fields of calcium ferrite, hexagonal phase and hollandite were determined in the systems MgAl_2O_4-Mg_2SiO_4, MgAl_2O_4-NaAlSiO_4 and KAlSi_3O_8, respectively, based on high-pressure experiments, calorimetry, and lattice vibrational modeling using Raman spectra.2. Formation of oxygen vacancies in perovskites in the system MgSiO_3-MgAlO_<2.5> was established by studies using ^<27>Al-NMR spectroscopy and X-ray Rietveld analysis. We concluded that two types of ionic substitutions (Mg^<2+>+Si^<4+> = 2Al^<3+> and 2Si^<4+> + O^<2-> = 2Al^<3+> +V^0) occur in the aluminous perovskites.3. High-pressure phase relations in CaMgSi_2O_6, CaSiO_3 and in the system CaTiSiO_5-CaSi_2O_5 were determined in detail. In phase transition study on SrSiO_3, we found new hexagonal perovskite of SrSiO_3 and new BaGe_2O_5III-type SrSi_2O_<5->.4. Enthalpies of formation were measured and stability relations were determined for various high-pressure A^<2+>B^<4+>O_3 perovskites. We found systematic relations between the enthalpies of formation and cationic radii. The relations provide useful guide to estimate enthalpies of formation and synthesis pressures of unknown perovskites.5. Standard entropies of Mg_2SiO_4 modified spinel and spinel were measured, and used to calculate olivine-modified spinel-spinel transitions and postspinel transition. The results indicated that the postspinel transition occurs at pressure of 660 km depth at about 1900 K, which confirms that the postspinel transition is responsible for the 660 km-discontinuity.6. Post-perovskite transition boundary of CaIrO_3 has a strongly positive P-T slope, consistent with that of MgSiO_3.

1。在系统MGAL_2O_4-MG_2SIO_4，MGAL_2O_4-NAALSIO_4和KALSI_3O_8的系统中确定钙铁氧体，六边形期和荷兰石的高压稳定性场，基于高压实验，加calorimetry和lattronic virlational模型，分别使用RAM.2。通过使用 ^<27> al-NMR光谱和X射线rietveld分析的研究，通过研究建立了系统MGSIO_3-MGALO_ <2.5>的钙晶的氧空位。我们得出结论，两种类型的离子取代（mg^<2+>+si^<4+> = 2al^<3+>和2SI^<4+>+o^<2-> = 2al^<3+>+v^0）出现在铝的perovskites.3中。3。详细确定了CAMGSI_2O_6，CASIO_3和系统Catisio_5-Casi_2O_5中的高压相位关系。在SRSIO_3的阶段过渡研究中，我们发现了SRSIO_3和新的BAGE_2O_5IIII-TYPE SRSI_2O_2O_ <5-> 4的新的Hexagonal Perovskite。测量形成的焓，并确定各种高压A^<2+> b^<4+> O_3 perovskites的稳定性关系。我们发现形成焓和阳离子半径之间的系统关系。该关系提供了有用的指南，以估计不明的钙钛矿的形成和合成压力的焓5。测量了MG_2SIO_4的标准熵，测量了修饰的尖晶石和尖晶石，并用于计算橄榄石修饰的尖晶石旋转旋转过渡和螺旋后旋转过渡。结果表明，后跨度的过渡发生在约1900 K时660 km深度的压力下发生，这证实后跨度的转变负责660 km近距离。6。 Cairo_3的植物后晶晶过渡边界具有强烈的P-T斜率，与MGSIO_3的斜坡一致。