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Updated: Jul 12, 2026
06:04
Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
Structural evolution of iron oxides melts at Earth's outer-core pressures.
Céline Crépisson1, Mila Fitzgerald2, Domenic Peake2
1Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK. celine.crepisson@physics.ox.ac.uk.
Nature Communications
|July 10, 2026
Summary
Light elements like oxygen in Earth
Area of Science:
- Geophysics and High-Pressure Mineral Physics
Background:
- Oxygen and light elements constitute up to 5 wt% of Earth's outer core.
- These elements significantly influence the geodynamo and core physical properties.
Purpose of the Study:
- To investigate the structural behavior of iron-oxygen melts under extreme pressures.
- To understand the role of oxygen's oxidation state on its solubility in liquid iron.
- To explore implications for Earth's uppermost outer core structure.
Main Methods:
- In situ X-ray diffraction measurements.
- Laser-driven shock compression at an X-ray Free-Electron Laser.
- Experiments on Fe, Fe + 4.5 FeO, and Fe2O3 melts at 177-440 GPa.
Main Results:
- Iron-oxygen melts exhibit predominantly four-fold coordination environments (4.0-4.5).
- Compressed melts show denser packing due to shorter Fe-Fe interatomic distances.
- Oxidation state modulates oxygen solubility in liquid iron, evidenced by structural differences.
Conclusions:
- High Fe-O coordination in Fe2O3 melts at 177 GPa suggests local oxygen variations.
- These variations may contribute to the inferred stratification in the uppermost outer core.
- Findings provide insights into the composition and dynamics of Earth's core.
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