Sound wave velocities and elastic constants for magnesiowustite using gigahertz interferometry

H. J. Reichmann, S. D. Jacobsen, S. J. Mackwell, C. A. McCammon

Research output: Contribution to journalArticlepeer-review

203 Scopus citations

Abstract

Ultrasonic interferometry at near-gigahertz frequencies is used to investigate longitudinal sound wave velocities parallel to [100] and [111] and the elastic constant c11 for high quality single crystals of magnesiowustite (Mg, Fe)O. The measurements were made at room pressure and temperature on samples spanning the full compositional range from periclase (MgO) to wustite (Fe(1-x)O). A strong P-wave anisotropy of ˜10% was measured for periclase, increasing about 1% for Mg0.94Fe0.06O then decreasing linearly to ˜0% for wustite. The elastic modulus c11 of magnesiowustite decreases linearly with iron content by -0.72(3) GPa/mol% FeO with the exception of a sharp increase for pure periclase. Thus, the addition of a small amount of iron to periclase has a major effect on its elastic behavior. This observation indicates that the use of a simple interpolation of elastic constant data between periclase and wustite [Jackson, 1998] may yield erroneous predictions for lower mantle compositions based on seismic data.

Original languageEnglish (US)
Pages (from-to)799-802
Number of pages4
JournalGeophysical Research Letters
Volume27
Issue number6
DOIs
StatePublished - Mar 15 2000

ASJC Scopus subject areas

  • Geophysics
  • General Earth and Planetary Sciences

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