Melting in the Fe-FeO system to 204 GPa: Implications for oxygen in Earth's core.
- Resource Type
- Article
- Authors
- Oka, Kenta; Hirose, Kei; Tagawa, Shoh; Kidokoro, Yuto; Nakajima, Yoichi; Kuwayama, Yasuhiro; Morard, Guillaume; Coudurier, Nicolas; Fiquet, Guillaume
- Source
- American Mineralogist. Nov2019, Vol. 104 Issue 11, p1603-1607. 5p.
- Subject
- *EARTH'S core
*LIGHT elements
*KILLER cells
*OXYGEN
- Language
- ISSN
- 0003-004X
We performed melting experiments on Fe-O alloys up to 204 GPa and 3500 K in a diamond-anvil cell (DAC) and determined the liquidus phase relations in the Fe-FeO system based on textural and chemical characterizations of recovered samples. Liquid-liquid immiscibility was observed up to 29 GPa. Oxygen concentration in eutectic liquid increased from >8 wt% O at 44 GPa to 13 wt% at 204 GPa and is extrapolated to be about 15 wt% at the inner core boundary (ICB) conditions. These results support O-rich liquid core, although oxygen cannot be a single core light element. We estimated the range of possible liquid core compositions in Fe-O-Si-C-S and found that the upper bounds for silicon and carbon concentrations are constrained by the crystallization of dense inner core at the ICB. [ABSTRACT FROM AUTHOR]