R3：高圧科学・地球深部

[R3-11] Reaction between water and iron in the early magma ocean and the present core-mantle boundary

*Yongjae Lee¹ (1. Yonsei University)

キーワード：Hydrogen, Magma ocean, Core-mantle boundary

Recent interest in hydrogen as a clean geological resource has been escalating, leading to active research on the formation and exploration of natural hydrogen worldwide. Paradoxically, however, hydrogen is the most abundant element in the universe and is also widely distributed in the Earth, as contained in mineral structures from the crust to the core. Hydrogen in minerals can exist in the form of molecular water (H2O), hydroxyl group (OH), or monatomic hydrogen (H), and is, therefore, directly related to the global transport and distribution of water. From this perspective, it is notable that the hydrogen budget increases innards to the mantle transition zone, lower mantle, and core, compared to the amount in the hydrosphere on the Earth’s surface. In this presentation, I will introduce the reactions between water and iron based on two recent experimental results to simulate the conditions of the early magma ocean [1] and the present core-mantle boundary [2], which could be linked to the initial distribution of hydrogen and its enrichment in the topmost outer core.

[1] J. Choi, R.J. Husband, H. Hwang, T. Kim, Y. Bang, S. Yun, J. Lee, H. Sim, S. Kim, D. Nam, B. Chae, H.-P. Liermann, Y. Lee*, Oxidation of iron by giant impact and its implication on the formation of reduced atmosphere in the early Earth, Science Advances, Vol.9, eadi6096, 2023
[2] T. Kim, J.G. O’Rourke, J. Lee, S. Chariton, V. Prakapenka, R.J. Husband, N. Giordano, H.-P. Liermann, S.-H. Shim*, Y. Lee*, “A hydrogen-enriched layer in the topmost outer core sourced from deeply subducted water”, Nature Geoscience, Vol.16, 1208-1214, 2023