Pressure dependence of u parameter in ringwoodite up to 7.9 GPa

Yasuhiro Kudoh, Takahiro Kuribayashi, Hiroki Mizobata, Eiji Ohtani, Satoshi Sasaki, Masahiko Tanaka

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

X-ray diffraction intensities were measured for single-crystal, spinel structure ringwoodite (γ-Mg1.97SiH0.03O4) at pressures up to 7.9 GPa in the BL-10A synchrotron beam line of the Photon Factory. The isothermal bulk modulus calculated using the Birch-Murnaghan equation of state assuming KT'=4 was KT=184(6) GPa. The difference between this result and the value for anhydrous ringwoodite is not significant within the limit of experimental error due to a minimal H2O content. The oxygen positional parameter u was revealed to increase significantly with pressure, approaching the ideal value of 1/4 for cubic closest packing. The mean Si-O distance remained almost constant up to 7.9 GPa, with compression of the unit cell occurring in proportion to that of the MO6 octahedron.

Original languageEnglish
Pages (from-to)8-11
Number of pages4
JournalJournal of Mineralogical and Petrological Sciences
Volume102
Issue number1
DOIs
Publication statusPublished - 2007 Feb 23

Keywords

  • Bulk modulus
  • Crystal structure
  • Silicate spinel
  • U parameter

ASJC Scopus subject areas

  • Geophysics
  • Geology

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