TY - JOUR
T1 - Single-crystal elasticity of γ-(Mg0.91Fe0.09)2 SiO4 to high pressures and to high temperatures
AU - Sinogeikin, Stanislav V.
AU - Bass, Jay D.
AU - Katsura, Tomoo
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2001/11/15
Y1 - 2001/11/15
N2 - 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.
AB - 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.
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U2 - 10.1029/2001GL013843
DO - 10.1029/2001GL013843
M3 - Article
AN - SCOPUS:0035891817
SN - 0094-8276
VL - 28
SP - 4335
EP - 4338
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 22
ER -