Experimental study on the melting relation of silicate under the lowermost mantle condition

下地幔条件下硅酸盐熔融关系的实验研究

基本信息

批准号：
16340164
负责人：
KONDO Tadashi
金额：
$ 10.56万
依托单位：
Osaka University (2006)Tohoku University (2004-2005)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

In this research project, we investigated the phase relation of the minerals under the lowermost mantle condition and the chemical reaction between those minerals and molten iron up to the condition corresponding to the earth's core-mantle boundary. For realizing such extreme conditions, we newly designed a symmetrical diamond anvil cell with a wide conical window for laser-heating and optical spectroscopy. The laser-heating system was also refined for stable heating and optimal temperature measurement from the hot sample by a spectroradiometric method. Experiments were performed using these techniques at SPring-8 and Photon Factory for in-situ X-ray diffraction measurements at high P-T, and also at laboratory for recovery runs to check the quenched samples. Thanks for the recent advances in micro-processing technologies such as laser cutting, focused ion beam, we successfully prepared the thin section of the recovered samples for analytical transmission electron microscopy. Finally we … More obtained the following results. (1) The chemical reaction between molten iron and perovskite and post-perovskite phase and wetting property at the core-mantle boundary condition was examined, and silicon and oxygen turned to be important candidates as light elements in the outer core. The wetting angle between post-perovskite phase and molten iron was slightly higher than the critical angle of 60°, which means 2wt% of the core material can be trapped in the D" layer. (2) Magnesiowustite is the heaviest minerals overall the mantle based on the iron partitioning experiments between magnesium oxide and silicate perovskite and post-perovskite phase. No evidence for the effect of a high-spin to low-spin transition was found in these minerals. (3) Potassium can be dissolved into molten iron significantly at core-mantle boundary condition, and the element may work as a heat source in the core. (4) The hydrous mineral, delta-AIOOH, has a wide stability field over 100GPa and 2000K, therefore this phase at relatively low temperature condition in descending slab possibly survive to the lowermost mantle to supply the water to core-mantle boundary. (5) Potassium bearing silicate with post-hollandite structure can be stably exist at the lowermost mantle condition. Less

在该研究项目中，我们研究了在最低地幔条件下矿物质的相位关系，这些矿物质与熔融熨斗之间的化学反应到与地球核心掩体边界相对应的条件。为了实现这种极端条件，我们新设计了一个对称的钻石砧细胞，该细胞具有广泛的临床窗口，用于激光加热和光谱。还将对激光加热系统进行完善，以通过光谱测量方法从热样品中进行稳定的加热和最佳的温度测量。使用这些技术在Spring-8和Photon工厂进行实验，以在高P-T时进行原位X射线衍射测量，并在实验室进行恢复运行以检查淬灭的样品。感谢您在微处理技术（例如激光切割，聚焦离子束）上的最新进展，我们成功地准备了回收样品的薄部分，以进行分析传输电子显微镜。最后，我们……更多获得以下结果。（1）检查了熔融铁和钙钛矿与磨牙后相之间的化学反应以及在核心掩体边界条件下的润湿特性，而硅和氧气变成了重要的候选者，作为外部芯中的光元素。绿化后相和熔融铁之间的润湿角略高于60°的临界角度，这意味着可以将核心材料的2wt％捕获在d“层中。（2）镁层岩石是基于氧化镁含量和硅质含量的含量的iCON分配实验的总体矿物质。在这些矿物质（3）中发现了低自旋的转变。边界（5）具有荷兰后结构的钾含量稳定在最低的地幔条件下