A perovskitic lower mantle inferred from high-pressure, high-temperature sound velocity data

  title={A perovskitic lower mantle inferred from high-pressure, high-temperature sound velocity data},
  author={M. Murakami and Y. Ohishi and N. Hirao and K. Hirose},
The determination of the chemical composition of Earth’s lower mantle is a long-standing challenge in earth science. Accurate knowledge of sound velocities in the lower-mantle minerals under relevant high-pressure, high-temperature conditions is essential in constraining the mineralogy and chemical composition using seismological observations, but previous acoustic measurements were limited to a range of low pressures and temperatures. Here we determine the shear-wave velocities for silicate… Expand
Is the mantle chemically stratified? Insights from sound velocity modeling and isotope evolution of an early magma ocean
Abstract The upper mantle is widely accepted to be pyrolitic, but the bulk composition of the lower mantle remains highly disputed. Recent modeling of the lower mantle shear wave velocity profile hasExpand
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The most popular model of the lower mantle is the Preliminary Reference Earth Model (PREM) , derived from seismic observations assuming the pyrolitic composition of the lower mantle. The uppermostExpand
Chapter 2 General Physical and Chemical Models of the Earth ’ s Lower Mantle
  • 2017
The most popular model of the lower mantle is the Preliminary Reference Earth Model (PREM), derived from seismic observations assuming the pyrolitic composition of the lower mantle. The uppermostExpand
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Effects of chemical, mineralogical, and temperature variations on the density and bulk sound velocity of the bottom lower mantle
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Density profile of pyrolite under the lower mantle conditions
[1] The pyrolite model is one of the possible compositions of the Earth's lower mantle. The lower mantle's composition is generally modelled by comparing seismic observations with mineral physicsExpand
Lower mantle composition and temperature from mineral physics and thermodynamic modelling
SUMMARY A generalized inverse method is applied to infer the radial lower mantle composition and temperature profile from seismological models of density and bulk sound velocity. The computations areExpand
Elasticity of MgO to 130 GPa: Implications for lower mantle mineralogy
Abstract The aggregate shear wave velocities of MgO (periclase) have been determined throughout Earth's lower mantle pressure regime approaching 130 GPa using Brillouin spectroscopy in conjunctionExpand
High‐pressure sound velocities and elasticity of aluminous MgSiO3 perovskite to 45 GPa: Implications for lateral heterogeneity in Earth's lower mantle
[1] 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,Expand
Iron Partitioning in Earth's Mantle: Toward a Deep Lower Mantle Discontinuity
A high-spin to low-spin transition occurring in the 60- to 70-gigapascal pressure range, corresponding to depths of 2000 kilometers in Earth's lower mantle, implies that the partition coefficient of iron between ferropericlase and magnesium silicate perovskite, the two main constituents of the lower mantle), may increase by several orders of magnitude. Expand
Sound velocity of MgSiO3 post-perovskite phase: A constraint on the D
Abstract The discovery of a post-perovskite phase transition in MgSiO 3 has significant implications for seismological observations in the D ″ region at the bottom of Earth's mantle. The D ″Expand
Pressure-induced changes in the compression mechanism of aluminous perovskite in the Earth's mantle
The results show that perovskites with oxygen vacancies do have significantly greater compressibilities than those without such vacancies, but the results suggest that oxygen vacancies become unfavourable at high pressures, in which case only the physical properties of the shallow lower mantle would be affected by aluminium. Expand
Development of in situ Brillouin spectroscopy at high pressure and high temperature with synchrotron radiation and infrared laser heating system: Application to the Earth's deep interior
Abstract Seismic wave velocity profiles in the Earth provide one of the strongest constraints on structure, mineralogy and elastic properties of the Earth's deep interior. Accurate sound velocityExpand
Chemical composition and origin of the earth's primitive mantle
Abstract An attempt has been made to estimate the chemical composition of the earth's primitive mantle by a critical evaluation of data derived from ultramafic mantle samples and partial meltingExpand
Sound velocities and elasticity of aluminous MgSiO3 perovskite: Implications for aluminum heterogeneity in Earth's lower mantle
Aluminum has been reported to have a remarkably strong effect on the thermoelastic properties of MgSiO_3 perovskite. However, the sound velocities of aluminous MgSiO_3 perovskite have not beenExpand