CAREER: Volatiles in the Earth's Interior: A combined theoretical and experimental approach

地球是一个水行星，70%的表面被水覆盖，占地球质量的0.025%。然而，水在深处的分布和储存程度在很大程度上仍然不受限制。然而，水对地球物质的几乎所有物理和化学性质都有很大的影响。这包括降低粘度和地震速度，同时提高导电性。结合观测到的下地幔黏度增加、从上地幔到下地幔的质量通量以及下地幔主要矿物的储水能力不足，说明下地幔是干燥的，导致了过渡带底部的过渡带水过滤器假说。或者，上下地幔之间的粘度对比可以通过上下地幔之间主要储水模式的变化来解释，而不需要这样的水过滤器。储存在上地幔主要矿物中的氢随后被储存在下地幔的次要矿物中，使得下地幔的大部分体积干燥而坚硬。为了验证这一提议的中心假设，这项工作将结合高压和温度实验测量，使用开创性的微加工样品用于理论计算。这将阐明深层水的存在导致地震波速度、粘度和电导率变化的潜在物理和化学过程。这项工作的结果广泛适用于地球科学和其他领域，对冰川均衡调整对当今海平面上升的影响以及固体氧化物燃料电池的设计都有影响。含水稀土钙钛矿是一种很有潜力的固体氧化物燃料电池材料。了解这些材料的水化机理，以及水化的温度稳定性极限，可以更好地设计这些装置。对深土硅酸盐钙钛矿中活性缺陷机制的认识将转化为这些稀土钙钛矿，从而允许设计更高效、更坚固的sofc。该职业奖还将帮助开发几个学习模块，将地球物理概念和方法整合到地球科学课程的课程中。特别地，这些模块将侧重于科学探索中的多变量推理。将通过对现有和待开发的概念测试进行前后测试来评估这些模块的有效性。这些模块将在PI的课程中创建和测试，然后集成到俄勒冈州立大学地球科学学院的课程中。

Earth is the water planet, with 70% of the surface covered by water and accounting for 0.025% of the mass of the planet. The degree to which water is distributed and stored at depth, however, remains largely unconstrained. Yet water has a great influence on almost all of the physical and chemical properties of earth materials. This includes lower viscosity and seismic velocities, while enhancing electrical conductivity. Together with the observed viscosity increase in the lower mantle, observed mass flux from the upper to lower mantle, and lack of water storage capacity of the major minerals of the lower mantle, this suggests that the lower mantle is dry, leading to a transition zone water filter hypothesis at the base of the transition zone. Alternatively, the viscosity contrast between the upper and lower mantle can be explained without such a water filter by a change in the dominant mode of water storage between the upper and lower mantle. The hydrogen stored in the major minerals of the upper mantle is then stored in minor minerals of the lower mantle, leaving most of the volume of the lower mantle dry and stiff. To test the central hypothesis of this proposal, this work will combine high-pressure and temperature experimental measurements using pioneering microfabricated samples for use in with theoretical computations. This will clarify the underlying physical and chemical processes responsible for variations in seismic wave speeds, viscosity, and electrical conductivity resulting from the presence of water at depth. The results of this work are broadly applicable to the field of Earth Science and beyond, with implications on the effects of glacial isostatic adjustment on present-day sea level rise to the design of solid-oxide fuel cells. Water-bearing rare-earth perovskites are potential solid-oxide fuel cell (SOFC) materials. A clear understanding of the mechanism of hydration of these materials, as well as the temperature stability limit of hydration can allow for a better design of these devices. Appreciation of the defect mechanisms active in deep-earth silicate perovskites will translate to these rare earth perovskites to allow for design of more efficient and more robust SOFCs. This CAREER award will also aid in development of several learning modules that integrate geophysical concepts and methods into courses taught across an earth science curriculum. In particular, these modules will have a focus on multivariant reasoning in scientific exploration. The effectiveness of these modules will be evaluated by pre- and post-testing of existing and to-be-developed ConcepTests. These modules will be created and tested in the PI's courses and later integrated into OSU's School of Earth Sciences courses.