Single-crystal elasticity of γ-(Mg0.91Fe0.09)2 SiO4 to high pressures and to high temperatures

Stanislav V. Sinogeikin, Jay D. Bass, Tomoo Katsura

Research output: Contribution to journalArticlepeer-review


Sound velocities and elastic moduli have been measured on γ-(Mg0.91Fe0.09)2 SiO4 (ringwoodite) single-crystals to 16 GPa and to 923K by Brillouin spectroscopy. A third-order finite-strain fit to the data yields pressure derivatives of 4.1(2) and 1.3(1) for the adiabatic bulk modulus (Ks) and shear modulus (μ) respectively. Mg-rich α, β, and γ (Mg,Fe)2SiO4 have identical values of ∂Ks/∂P and of ∂μ/∂P within the experimental uncertainties. ∂Ks/∂T and ∂μT/∂T for γ-(Mg,Fe)2SiO4 are -0.021 and -0.016 GPa/K respectively. Our results indicate that the shear and compressional impedance contrasts associated with β- → γ-(Mg,Fe)2SiO4 transition are sufficient to produce a visible discontinuity at 520 km even with a moderate (30-50%) amount of olivine. The generally low visibility of the 520 km discontinuity is likely due to its width and large amplitude topographic variations.

Original languageEnglish (US)
Pages (from-to)4335-4338
Number of pages4
JournalGeophysical Research Letters
Issue number22
StatePublished - Nov 15 2001

ASJC Scopus subject areas

  • Geophysics
  • General Earth and Planetary Sciences


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