Study of the dynamics and the multisphere interaction of the Early earth

早期地球的动力学和多球体相互作用研究

• 批准号: 02302033
• 负责人: OHTANI Eiji
• 金额: $ 4.74万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Co-operative Research (A)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02302033/
• 关键词: Magma ocean; Plate tectonics; Kimberlite; Komatiite; Density of magma; Accretion; Archean; High pressure; コマチアイト; 地球核物質; Mg‐ペロブスカイト; マグマオ-シャン; 遷移金属元素; 分配; 初期地球; 多圏相互作用; 中央海嶺玄武岩; 付加体; リソスフェア; シミュレ-ション

Following topics were studied during this Co-operative research (A) project. Numerical simulation was conducted to clarify the process of formation of the terrestrial magma ocean during the accretion and formation of the primitive crust in the magma ocean stage. The high pressure experiments showed that a density crossover between olivine and the FeO rich peridotite magma of the Martian mantle composition occurs at around 7 GPa, which corresponds to the depth of about 600 km of the Martian interior. The similar density crossover is expected to occur at about 12 GPa which corresponds to the depth of 350 km in the terrestrial mantle. Petrogenesis of magmas observed in the early stage of the terrestial evolution, such as komatiite and kimberlite was also studied by using the multianvil high pressure apparatus. Tectonics of the early stage of the earth was also studied on the basis of the field work on geology of the Archean terrains, and showed that the tectonic style of the early Archean to 3.9 Ga ago was essentially similar to the modern plate tectonics. The high pressure research was conducted to study the phase transformation of the descending slab and the thermodynamic properties of the lower mantle minerals were also studied to discuss the secular change of the chemistry of the deep mantle. The symposium of this co-operative reserch was held during the 1993 joint meeting of the societies of the Earth and Planetary Sciences.

本合作研究 (A) 项目期间研究了以下主题。通过数值模拟，阐明了岩浆洋阶段原始地壳的吸积形成过程中陆地岩浆洋的形成过程。高压实验表明，橄榄石和火星地幔成分中富含FeO的橄榄岩岩浆之间的密度交叉发生在7 GPa左右，相当于火星内部约600公里的深度。类似的密度交叉预计会发生在大约 12 GPa 处，相当于地幔 350 公里的深度。还利用多砧高压装置对科马提岩、金伯利岩等陆地演化早期观测到的岩浆的岩石成因进行了研究。在太古代地形野外地质工作的基础上，对地球早期构造进行了研究，表明太古代早期至3.9 Ga前的构造样式与现代板块构造基本相似。通过高压研究来研究下降板片的相变，并研究下地幔矿物的热力学性质，以讨论深部地幔化学的长期变化。这项合作研究的研讨会是在1993年地球与行星科学学会联席会议期间举行的。