Element Partitioning in Earth's Deep Magma Ocean

Carnegie Institution Of Washington, Washington DC

Investigators

Abstract

Energetic giant impacts such as the Moon-forming impact would lead to a global magma ocean on Earth in its early history. The heavy metallic materials would separate from the molten silicate mantle in the Earth’s deep magma ocean to form the metallic core. The process leaves a distinct mantle chemical signature and defines the core chemical composition. With development of high-temperature and high-pressure techniques combined with analytical tools, the team will simulate the conditions of the deep magma ocean in the laboratory and determine the distribution of elements during the metal-silicate separation. The project will produce unprecedented high-quality metal-silicate element partitioning data that are necessary for understanding the chemistry and evolution of our planet and lead to new frontiers for cutting-edge research. The program provides training for young scientists in interdisciplinary research areas and develops new experimental techniques that will benefit a broad Solid Earth community. The results will be disseminated broadly to advance science in geochemistry and promote general understanding of Earth science in society. The research is aimed at determining the element partitioning between liquid silicate and metal by using the newly developed large sintered-diamond cube assembly in the multi-anvil press and improved laser-heated diamond-anvil-cell sample configuration combined with state-of-the-art sample recovery and analytical tools. Specific projects include (1) determining potassium partitioning between liquid metal and silicate to quantify the radioactive energy contribution to the core in the deep magma ocean scenario, and (2) establishing the effect of pressure, temperature, and composition on the silicon and oxygen partition coefficients. The experiments will provide new partitioning data for potassium, silicon, and oxygen to be used to quantify the heat budget and the amounts of light elements sequestered into the core. The proposed work will significantly advance our knowledge of Earth’s deep processes and experimental techniques to investigate the composition of the Earth’s deep interior. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.