Solubility of FeO in (Mg,Fe)SiO3 perovskite and the post-perovskite phase transition

Shigehiko Tateno, Kei Hirose, Nagayoshi Sata, Yasuo Ohishi

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    71 Citations (Scopus)

    Abstract

    Phase relations in Mg0.5Fe0.5SiO3 and Mg0.25Fe0.75SiO3 were investigated in a pressure range from 72 to 123 GPa on the basis of synchrotron X-ray diffraction measurements in situ at high-pressure and -temperature in a laser-heated diamond-anvil cell (LHDAC). Results demonstrate that Mg0.5Fe0.5SiO3 perovskite is formed as a single phase at 85-108 GPa and 1800-2330 K, indicating a high solubility of FeO in (Mg,Fe)SiO3 perovskite at high pressures. Post-perovskite appears coexisting with perovskite in Mg0.5Fe0.5SiO3 above 106 GPa at 1410 K, the condition very close to the post-perovskite phase transition boundary in pure MgSiO3. The coexistence of perovskite and post-perovskite was observed to 123 GPa. In addition, post-perovskite was formed coexisting with perovskite also in Mg0.25Fe0.75SiO3 bulk composition at 106-123 GPa. In contrast to earlier experimental and theoretical studies, these results show that incorporation of FeO stabilizes perovskite at higher pressures. This could be due to a larger ionic radius of Fe2+ ion, which is incompatible with a small Mg2+ site in the post-perovskite phase.

    Original languageEnglish
    Pages (from-to)319-325
    Number of pages7
    JournalPhysics of the Earth and Planetary Interiors
    Volume160
    Issue number3-5
    DOIs
    Publication statusPublished - Mar 16 2007

    Keywords

    • D″ layer
    • In situ X-ray observation
    • Iron
    • Perovskite
    • Phase transition
    • Post-perovskite

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Geophysics
    • Physics and Astronomy (miscellaneous)
    • Space and Planetary Science

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