Element Partitioning at Earth's Deep Chemical Boundaries

Carnegie Institution Of Washington, Washington DC

Investigators

Abstract

The Earth's core-mantle boundary (CMB) and inner core boundary (ICB) are the most important deep chemical boundaries that define the dynamics of the interior and control the generation of Earth magnetic field. The boundaries reset the element redistribution through metal-silicate differentiation and inner crystallization. The goal of this study is to understand the behavior of element partitioning at these boundaries using newly developed high-pressure and temperature techniques and state-of-the-art analytical tools that allow simulating the conditions of the boundaries and analyzing the chemical compositions of the coexisting phases in the recovered samples. The proposed work will significantly advance our knowledge of Earth's deep processes and experimental techniques to investigate element redistribution at deep chemical boundaries. The focus of the proposed research is on the silicon (Si) and oxygen (O) partitioning between mantle and core at high pressure and temperature, applicable to core-mantle differentiation and the incorporation of Si and O in the core. Specific projects include (1) determining the Si and O partitioning between liquid mantle silicate and molten core iron alloy up to CMB pressure, and (2) determining the effect of pressure on the Si, O, and S partitioning coefficients between solid and liquid iron alloy and examining their partitioning behavior at ICB conditions. The research will produce high-quality data under extreme conditions that are necessary for understanding the chemistry of Earth's core and providing insight into the Earth accretion environment and the evolution of Earth's interior. It will open new research opportunities at the interface of petrology, mineral physics, geochemistry, and geophysics.