Physics and Chemistry of Planetary Materials at Extreme Conditions

极端条件下行星材料的物理和化学

• 批准号: RGPIN-2014-04612
• 负责人: Shieh, Sean
• 金额: $ 2.7万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=665056
• 关键词: Physics; Chemistry; Planetary; Materials; Extreme

The objective of my research is to improve our abilities to understand the deep interior dynamics and evolution of Earth and other planets. The dynamics and evolution of Earth's and planetary interiors will influence the outermost features of the Earth and other planets. However, Earth's and planetary interiors are inaccessible and cannot be directly investigated. Alternative approaches are to study Earth and planetary materials at simulated environments that are similar to Earth and planetary interiors. In addition, behavior of materials at ambient conditions (1 atm and 25 C) is different from what they exhibit at greater depths. Therefore, only those data collected at pressure and temperature conditions corresponding to the certain depths are valid for modeling the structure and dynamics of the Earth's and planetary interiors. Therefore, study of Earth and planetary materials at pressure and temperature conditions corresponding to their deep interiors provide promising approach to understand the dynamics and evolution of Earth's and planetary interiors. **My research program uses high pressure apparatus, a diamond-anvil cell (DAC, able to generate pressure from 1 to 3,000,000 atm) together with resistive and laser heating methods (able to heat the sample to 3000 - 4000 K), to study planetary materials under extreme pressure and temperature conditions. The extensive pressure and temperature ranges (1 - 3,000,000 atm and 300 - 4000 K) allow us to replicate the conditions found within the Earth and planetary interiors. Moreover, using a custom-built micro-Raman system and synchrotron infrared spectroscopy, the spectroscopic properties of relevant materials are also examined. **In this proposal, we synthesize the important deep mantle phases (e.g. aluminum and iron-rich perovskite and post-perovskite, carbon- and hydrogen-bearing silicates, spinels, oxides and iron alloys) and characterize them using synchrotron x-ray diffraction, x-ray spectroscopy, Raman and infrared to understand their structures and physical properties (e.g. density, volume, elasticity, strength, stress). The synthesized samples when quenched to ambient conditions will be examined by electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and analytical transmitting electron microscopy (ATEM) for understanding the partitioning of the elements and element distributions within the samples, the melting criteria of the iron alloy, and the crystal structures of the nano-scale phases. Our goals are (1) to understand the causes and mechanism of seismic anomalies (e.g. ultralow velocity) found within the D" layer, (2) to build a strength model of mixed mantle phases that can be applied to modeling the dynamics of the Earth's interior, (3) to evaluate the high pressure polymorphs of chromium spinel at high pressure-temperature conditions as well as its connection to the shocked meteorites, and (4) to evaluate the budgets of the hydrogen and carbon inside the Earth via the carbon- and hydrogen-bearing deep mantle phases. **The proposed projects will promote interdisciplinary work and education in the fields of mineral physics, geodynamics, planetary science and material science. In addition, HQP will receive well-rounded training in the high pressure research. They will use powerful analytical tools at UWO and state-of-the-art synchrotron facilities at different locations for their projects. Especially, HQP will greatly benefit from their participations in the synchrotron trips as they will have excellent opportunities to expose themselves to different fields of communities. This will be of great help for their future careers.

我研究的目的是提高我们理解地球和其他行星的深层内部动力学和演化的能力。地球和行星内部的动力学和演化将影响地球和其他行星的最外层特征。然而，地球和行星的内部是无法进入的，不能直接调查。另一种方法是在类似于地球和行星内部的模拟环境中研究地球和行星材料。此外，材料在环境条件（1 atm和25 C）下的行为与它们在更深处表现出的行为不同。因此，只有在对应于特定深度的压力和温度条件下收集的数据才能有效地模拟地球和行星内部的结构和动力学。因此，研究地球和行星材料在压力和温度条件下对应于他们的深部内部提供了有前途的方法来了解地球和行星内部的动力学和演化。** 我的研究计划使用高压装置，金刚石砧室（DAC，能够产生1到3，000，000 atm的压力），以及电阻和激光加热方法（能够将样品加热到3000 - 4000 K），以研究极端压力和温度条件下的行星材料。广泛的压力和温度范围（1 - 3，000，000 atm和300 - 4000 K）使我们能够复制地球和行星内部的条件。此外，利用定制的显微拉曼系统和同步辐射红外光谱，相关材料的光谱特性也进行了研究。** 在本提案中，我们合成了重要的深地幔相（例如富含铝和铁的钙钛矿和后钙钛矿、含碳和含氢的硅酸盐、尖晶石、氧化物和铁合金），并使用同步加速器X射线衍射、X射线光谱、拉曼和红外线对其进行表征，以了解其结构和物理性质（例如密度、体积、弹性、强度、应力）。将通过电子探针显微分析（EPMA）、扫描电子显微镜（SEM）和分析透射电子显微镜（ATEM）检查淬火至环境条件时的合成样品，以了解样品内的元素和元素分布的分配、铁合金的熔化标准和纳米级相的晶体结构。我们的目标是：（1）了解地震异常的原因和机制（例如超低速），（2）建立混合地幔相的强度模型，可用于模拟地球内部的动力学，（3）评估铬尖晶石的高压多晶型物在高压-温度条件下及其与冲击陨石的联系，（4）通过含碳和含氢的深地幔相估算地球内部的氢和碳收支。** 拟议的项目将促进矿物物理学、地球动力学、行星科学和材料科学领域的跨学科工作和教育。此外，HQP将接受全面的高压研究培训。他们将使用强大的分析工具在UWO和国家的最先进的同步加速器设施在不同的位置为他们的项目。特别是，HQP将极大地受益于他们的参与同步加速器之旅，因为他们将有很好的机会，使自己暴露在不同领域的社区。这将对他们未来的职业生涯有很大的帮助。