Two-stage spin transition of iron in FeAl-bearing phase D at lower mantle

Xiang Wu, Ye Wu, Jung Fu Lin, Jin Liu, Zhu Mao, Xinzhuan Guo, Takashi Yoshino, Catherine McCammon, Vitali B. Prakapenka, Yuming Xiao

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Hydrous magnesium silicate phase D plays a key role in the transport of water from the upper to the lower mantle via subducted slabs. Here we report pressure dependence hyperfine and lattice parameters of FeAl-bearing phase D up to megabar pressures using synchrotron nuclear forward scattering and X-ray diffraction in a diamond anvil cell at room temperature. FeAl-bearing phase D undergoes a two-stage high-spin to low-spin transition of iron for Fe2+ at 37–41 GPa and for Fe3+ at 64–68 GPa. These transitions are accompanied by an increase in density and a significant softening in the bulk modulus and bulk velocity at their respective pressure range. The occurrence of the dense low-spin FeAl-bearing phase D with relatively high velocity anisotropies in deep-subducted slabs can potentially contribute to small-scale seismic heterogeneities in the middle-lower mantle beneath the circum-Pacific area.

Original languageEnglish
Pages (from-to)6411-6420
Number of pages10
JournalJournal of Geophysical Research: Solid Earth
Volume121
Issue number9
DOIs
Publication statusPublished - Sep 1 2016

Keywords

  • lower mantle
  • phase D
  • spin transition of iron

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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    Wu, X., Wu, Y., Lin, J. F., Liu, J., Mao, Z., Guo, X., Yoshino, T., McCammon, C., Prakapenka, V. B., & Xiao, Y. (2016). Two-stage spin transition of iron in FeAl-bearing phase D at lower mantle. Journal of Geophysical Research: Solid Earth, 121(9), 6411-6420. https://doi.org/10.1002/2016JB013209