Stability field of phase Egg, AlSiO<sub>3</sub>OH at high pressure and high temperature: possible water reservoir in mantle transition zone

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Author(s)

    • FUKUYAMA Ko
    • Geochemical Research Center, Graduate School of Science, The University of Tokyo
    • OHTANI Eiji
    • Department of Earth Science, Graduate School of Science, Tohoku University
    • SHIBAZAKI Yuki
    • Department of Earth Science, Graduate School of Science, Tohoku University|Frontier Research Institute for Interdisciplinary Sciences, Tohoku University
    • KAGI Hiroyuki
    • Geochemical Research Center, Graduate School of Science, The University of Tokyo
    • SUZUKI Akio
    • Department of Earth Science, Graduate School of Science, Tohoku University

Abstract

<p>High–pressure and high–temperature experiments were conducted to determine the stability field of phase Egg, AlSiO<sub>3</sub>OH, in the pressure range of 16.5–23.5 GPa and in the temperature range of 800–1500 °C. We found that phase Egg decomposes to δ–AlOOH + stishovite below ~ 1200 °C (16.5 GPa and 800 °C; 20.6 GPa and 1000 °C) and to Al–phase D + corundum + stishovite above ~ 1200 °C (21.8 GPa and 1500 °C) at <i>P–T</i> conditions corresponding to the mantle transition zone.</p><p> This indicates that phase Egg is unstable at the top of the lower mantle and can be a water reservoir only in the mantle transition zone. In addition, the present results imply that the superdeep diamonds that include phase Egg do not originate from the lower mantle but from the wet mantle transition zone.</p>

Journal

  • Journal of Mineralogical and Petrological Sciences

    Journal of Mineralogical and Petrological Sciences 112(1), 31-35, 2017

    Japan Association of Mineralogical Sciences

Codes

  • NII Article ID (NAID)
    130005461018
  • Text Lang
    ENG
  • ISSN
    1345-6296
  • Data Source
    J-STAGE 
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