Physics and Chemistry of Minerals

, Volume 17, Issue 5, pp 416–419 | Cite as

Effects of Fe/Mg on the compressibility of synthetic wadsleyite: β-(Mg1-xFex)2SiO4 (x≤0.25)

  • Robert M. Hazen
  • Jinmin Zhang
  • Jaidong Ko
Article

Abstract

Four crystals of synthetic wadsleyite, β-(Mg,Fe)2SiO4, were mounted together in one diamond-anvil cell for the determination of unit-cell parameters as a function of pressure. The Fe/(Fe+Mg) are 0.00, 0.08, 0.16, and 0.25 (the most iron-rich stable composition). Unit-cell refinements were made at 12 pressures up to 4.5 GPa. No phase transitions were observed and all crystals remained dimensionally orthorhombic. Of the three axes, c is the most compressible (0.000239(3) GPa-1), whereas compressibilities of a and b are both about 30% less. The Fe content has no systematic effect on volume or linear compressibilities. Bulk moduli, based on a Birch-Murnaghan equation of state (K′ assumed to be 4.00) are 160(3), 169(3), 164(2), and 165(3) GPa for the four crystals in order of increasing Fe. Substitution of Fe for Mg, therefore, does not appear to have a systematic effect on bulk modulus. Other factors, especially Fe3+/Fe2+ and other deviations from the strict Mg2SiO4-Fe2SiO4 binary, may have a greater influence on compressibility.

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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Robert M. Hazen
    • 1
  • Jinmin Zhang
    • 1
  • Jaidong Ko
    • 2
  1. 1.Carnegie Institution of Washington, Geophysical LaboratoryWashington, DCUSA
  2. 2.Department of Earth and Space ScienceState University of New YorkStony BrookUSA

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