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Shock Compression and Phase Transitions of Magnesiowüstite (Mg,Fe)O up to Earth’s Lowermost Mantle Conditions |
| ZHANG Li1;GONG Zi-Zheng2,1 |
| 1Institute of High Pressure and High Temperature Physics, Southwest Jiaotong University, Chengdu 610031
2Beijing Institute of Spacecraft Environment Engineering, Beijing 100094 |
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| Cite this article: |
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ZHANG Li, GONG Zi-Zheng 2006 Chin. Phys. Lett. 23 3049-3051 |
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Abstract We report new shock-compression data for polycrystalline (Mg,Fe)O up to 130GPa shock pressures corresponding to Earth’s lowermost mantle conditions. Our data together with the existing shock-wave data of (Mg,Fe)O and its end-members MgO and FeO reveal that the Hugoniot curves of (Mg,Fe)O does not change with varying FeO content for their B1 phase (NaCl-structure) in the pressure--relative-volume plane. The evidence of the volume change within 3% at around 120GPa along the Hugoniot of (Mg0.6, Fe0.4)O is consistent with a structural transition from B1 phase (NaCl cubic) to B8 phase (NiAs-type hexagonal). Such a structural transition of (Mg,Fe)O, if indeed occurs, may in part contribute to the scattering of seismic waves and change in velocity gradient found in the lowermost mantle.
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| Keywords:
62.50.+p
64.30.+t
91.35.Lj
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Published: 01 November 2006
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