Research Highlight: Earth’s inner core may be oxygen-rich

on March 19, 2023

J. Liu, Y. Sun, C. Lv, F. Zhang, S. Fu, V. B. Prakapenka, C.-Z. Wang, K.-M. Ho, J.-F. Lin, R. M. Wentzcovitch. The Innovation (2022).

Press Highlights

Earth’s inner core may be oxygen-rich by EurekAlert, AAAS

Oxygen is the key substance for life and one of the most abundant elements in the Earth. However, it’s still unknown whether oxygen is present and in which form in the inner core with extreme high pressure and temperature conditions, and almost composed of pure iron. Scientists co-led by Dr. Jin Liu from HPSTAR (the Center for High Pressure Science &Technology Advanced Research) and Dr. Yang Sun from Columbia University reveal that Fe-rich Fe-O alloys are stable at extreme pressures of nearly 300 GPa and high temperatures of more than 3,000 K. The results published in the journal of The Innovation prove that oxygen can exist in the solid inner core, which provides key constraints for further understanding of the formation process and evolution history of the Earth’s core.

Earth’s inner core may be oxygen-rich by Center for High Pressure Science & Technology Advanced Research

Is the Earth’s inner core so “anoxic?” To answer this question, a series of experiments and theoretical calculations were carried out in this study.

To be close to the temperature and pressure of Earth’s core, pure iron and iron oxide were placed on the tips of two diamond anvils and heated with a high-energy laser beam. After many attempts, it was found that a chemical reaction between iron and iron oxide occurs above 220–260 GPa and 3,000 K. The XRD results reveal that the reaction product is different from the common high-temperature and high-pressure structure of pure iron and iron oxide.