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Licensed Unlicensed Requires Authentication Published by De Gruyter April 1, 2015

Ferric iron content in (Mg,Fe)SiO3 perovskite and post-perovskite at deep lower mantle conditions

  • Ryosuke Sinmyo EMAIL logo , Haruka Ozawa , Kei Hirose , Akira Yasuhara , Noriaki Endo , Nagayoshi Sata and Yasuo Ohishi
From the journal American Mineralogist

Abstract

We have determined the Fe3+/ΣFe ratio of Al-free (Mg,Fe)SiO3 perovskite, post-perovskite, and (Mg,Fe)O ferropericlase synthesized at 99 to 187 GPa and 1830 to 3500 K based on the electron energyloss near-edge structure (ELNES) spectroscopy. The results demonstrate that post-perovskite includes minor amounts of ferric iron with Fe3+/ΣFe ratios of 0.11 to 0.21. These values are substantially lower than those of Al-rich post-perovskite (Fe3+/ΣFe = 0.59 to 0.69) reported in a previous study, suggesting that the Fe3+-Al3+ coupled substitution is important in post-perovskite, as in the case of perovskite. The Al-bearing post-perovskite in a pyrolitic mantle composition likely contains a considerable amount of ferric iron, which affects various physical properties in the lowermost mantle.

Received: 2007-9-27
Accepted: 2008-5-20
Published Online: 2015-4-1
Published in Print: 2008-11-1

© 2015 by Walter de Gruyter Berlin/Boston

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