Sound velocities and elasticity of aluminous MgSiO3 perovskite: Implications for aluminum heterogeneity in Earth's lower mantle

Jennifer M. Jackson, Jianzhong Zhang, Jay D. Bass

Research output: Contribution to journalArticlepeer-review

Abstract

Aluminum has been reported to have a remarkably strong effect on the thermoelastic properties of MgSiO3 perovskite. However, the sound velocities of aluminous MgSiO3 perovskite have not been previously measured, even though this phase likely dominates most of the chemistry in Earth's lower mantle. Here we report the first sound velocity measurements on aluminous MgSiO3 perovskite using Brillouin spectroscopy and obtain the following values for the room-pressure room-temperature adiabatic bulk and shear moduli: Ks = 252 ± 5 GPa and μ = 165 ± 2 GPa, respectively. The presence of 5.1 ± 0.2 wt.% A12O3 in MgSiO3 perovskite decreases the shear modulus by 5.6%. However, within experimental uncertainties, there is no discernable effect of aluminum on the bulk modulus. We find that variations in the aluminum content Of MgSiO3 perovskite may provide an explanation for some observed lateral heterogeneity in Earth's lower mantle.

Original languageEnglish (US)
Pages (from-to)L10614 1-4
JournalGeophysical Research Letters
Volume31
Issue number10
DOIs
StatePublished - May 28 2004

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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