Experimental Constraints on Physical Mechanisms of Core Formation

了解有助于行星早期分化为岩石（硅酸盐）地幔和金属核心的化学和物理过程是了解地球演化的基础。有人提出，早期地球经历了广泛的熔融，在高压和高温下，所产生的金属液体与剩余的硅酸盐材料分离，形成了地核。一个全面的框架核心形成机制在部分熔融硅酸盐在晶粒尺度尚未完全建立。该项目利用最近开发的实验方法和成像技术，再加上数值模拟，以确定在与行星地球的分化有关的条件下，允许金属液体从部分熔融的硅酸盐中分离的物理过程，这项工作将解决在颗粒尺度上几种平衡和非平衡核心形成情景下的金属分离率。具体而言，部分熔融的硅酸盐熔体的不同程度的影响，不同的金属熔体的组成和持续变形的金属熔体的分布和流动性的影响将被量化。实验测量和数值模拟相结合的方法增加了一种新的方式来量化的三维几何形状和颗粒尺度流动性的核心形成熔体，还没有通过传统的估计渗透率和迁移速度。

Understanding both the chemical and physical processes that contribute to the early differentiation of planets into rocky (silicate) mantles and metallic cores is fundamental to the understanding of Earth's evolution. It has been proposed that the early Earth experienced wide spread melting, and the resulting metallic liquid segregated from the remaining silicate material at high pressures and temperatures forming the core. A comprehensive framework for core formation mechanisms in a partially molten silicate at the grain scale has not yet been fully established. This project utilizes recently developed experimental methods and imaging techniques coupled with numerical simulations to determine the physical processes that allow for segregation of metallic liquids from partially molten silicates at conditions relevant to the differentiation of the planet Earth.This work will address the rate(s) of metal segregation for several equilibrium and non-equilibrium core formation scenarios at the grain scale. Specifically, the effect varying degrees of partially molten silicate melt, different compositions of metallic melt and the influence of sustained deformation on the distribution and mobility of metallic melts will be quantified. The combined approach of experimental measurement and numerical simulation adds a new way of quantifying the three dimensional geometry and grain scale mobility of core forming melts that has not been available through traditional estimates of permeability and migration velocity.