Linking elastic and electrical properties to investigate partial melting in the deep mantle

Alisha Clark博士已获得NSF博士后奖学金，在西北大学和圣地亚哥加州大学斯克里普斯海洋学研究所开展研究和教育计划。该项目的重点是进行实验室实验，以确定玄武岩成分的硅酸盐熔体在高压和高温条件下的速度和电特性。硅酸盐熔体是传递热量和质量的最有效手段，在行星分化中发挥了关键作用。为了解释地球内部的物理状态，需要有与观测到的地球物理异常相对应的压力和温度的实验数据。这个跨学科的研究项目涵盖矿物物理学，岩石学，固体地球物理学，材料科学和凝聚态物理学的主题。克拉克博士将参与西北大学的兴奋项目，该项目旨在增加埃文斯顿镇高中荣誉科学和数学课程中代表性不足的少数民族学生的入学率。此外，她将指导本科生进行与该项目相关的研究。该研究将提供有关高压和高温下玄武岩熔体的弹性和电学性质的信息，以产生压力高达地球过渡区410-660 km的硅酸盐熔体的状态方程。为了实现这些目标，克拉克博士将使用西北大学最新一代的千兆赫兹超声干涉仪来限制高压和高温下的声速和弹性模量。此外，首席研究员将在斯克里普斯使用新的多砧系统，在高压和高温下对相同的硅酸盐熔体进行电导率测量，并将这些趋势与速度相关联，以及确定熔体分数对电导率的影响。调查的最后一部分将包括确定挥发分对玄武岩熔体速度和传导性的影响。从这次调查的结果将是重要的解释地球物理观测时，将提供限制的硅酸盐熔体的物理性质在深度大于tan 410公里。

Dr. Alisha Clark has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at Northwestern University and Scripps Institute of Oceanography at University of California, San Diego. The project will focus on conducting laboratory experiments to determine velocity and electrical properties of silicate melts of basaltic composition at high pressure and temperature conditions. Silicate melts are the most efficient means of transporting heat and mass and have played a critical role in planetary differentiation. Experimental data at pressure and temperatures corresponding to the observed geophysical anomalies are required to interpret the physical state of the Earth's interior. This interdisciplinary research project spans topics in mineral physics, petrology, solid-Earth geophysics, materials science, and condensed matter physics. Dr. Clark will be engaged in Project Excite at Northwestern University that aims increasing enrollment of underrepresented minority students in Evanston Township High School's honors science and mathematics courses. In addition, she will mentor undergraduate students in research related to this project.This investigation will provide information on both elastic and electrical properties of basaltic melts at high pressures and temperatures to produce an equation of state for silicate melts at pressures up to theEarth's transition zone, 410-660 km. To accomplish these goals, Dr. Clark will use the latest generation Gigahertz-ultrasonic interferometer at Northwestern University to constrain the acoustic velocities and elastic moduli at high pressure and temperatures. In addition, the principal investigator will use the new multi-anvil system at Scripps to perform electrical conductivity measurements on the same silicate melts at high pressures and temperatures and correlate these trends with velocity, as well as to determine the effect of melt fraction of electrical conductivity. The last component of the investigation will consist of determining the influence of volatiles on basaltic melt velocity and conductivity. The results from this investigation will be important when interpreting geophysical observations and will provide constrains on the physical properties of silicate melts at depths greater tan 410 km.