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High‐pressure sound velocities and elasticity of aluminous MgSiO 3 perovskite to 45 GPa: Implications for lateral heterogeneity in Earth's lower mantle
Author(s) -
Jackson Jennifer M.,
Zhang Jianzhong,
Shu Jinfu,
Sinogeikin Stanislav V.,
Bass Jay D.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl023522
Subject(s) - post perovskite , silicate perovskite , mineralogy , mantle (geology) , anorthite , brillouin spectroscopy , geology , perovskite (structure) , silicate , diamond anvil cell , brillouin scattering , bulk modulus , analytical chemistry (journal) , materials science , thermodynamics , geophysics , chemistry , high pressure , optics , crystallography , composite material , physics , organic chemistry , optical fiber , chromatography
Brillouin scattering measurements on aluminous magnesium silicate perovskite, arguably the most abundant phase in Earth, have been performed to 45 GPa in a diamond anvil cell at room temperature, using methanol‐ethanol‐water and neon as pressure transmitting media. The experiments were performed on a polycrystalline sample of aluminous MgSiO 3 perovskite containing 5.1 ± 0.2 wt.% Al 2 O 3 . The pressure derivatives of the adiabatic bulk ( K 0S ) and shear (μ 0S ) moduli are 3.7 ± 0.3 and 1.7 ± 0.2, respectively. These measurements allow us to evaluate whether the observed lateral variations of seismic wave speeds in Earth's lower mantle are due at least in part to a chemical origin. Our results indicate that a difference in the aluminum content of silicate perovskite, reflecting a variation in overall chemistry, is a plausible candidate for such seismic heterogeneity.