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Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
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Stratification in planetary cores by liquid immiscibility in Fe-S-H
Shunpei Yokoo1, Kei Hirose2,3, Shoh Tagawa2,3
1Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan. shunpei@eps.s.u-tokyo.ac.jp.
Nature Communications
|February 4, 2022
Summary
Iron alloys exhibit liquid immiscibility at high pressures, crucial for planetary cores. This study reveals immiscible liquids in Martian core conditions (~20 GPa) and potentially Earth
Area of Science:
- Geophysics
- Planetary Science
- High-Pressure Mineral Physics
Background:
- Liquid-liquid immiscibility in iron alloys is known at ambient pressure and influences planetary core dynamics.
- Previously, immiscibility was thought to vanish at low pressures, necessitating further investigation under extreme conditions.
Purpose of the Study:
- To investigate liquid-liquid immiscibility in iron alloys at high pressures relevant to planetary cores.
- To determine the conditions under which immiscibility occurs in Fe-S-H(±Si,O,C) systems.
Main Methods:
- High-pressure experiments simulating core conditions.
- Analysis of immiscible liquid formation in iron-sulfur-hydrogen systems.
Main Results:
- Discovery of immiscible S(±Si,O)-rich and H(±C)-rich liquids above ~20 GPa, relevant to the Martian core.
- Observation of liquid immiscibility in Fe-S-H(±Si,O,C) up to 118 GPa, suggesting implications for Earth's outer core.
Conclusions:
- The observed immiscibility in the Martian core composition could explain its core convection and magnetic field history.
- Immiscibility in Earth's upper outer core may form a low-velocity layer beneath the core-mantle boundary.
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