Zhang, S, Cottaar, S, Liu, T et al. (2 more authors) (2016) High-pressure, temperature elasticity of Fe- and Al-bearing MgSiO3: implications for the Earth’s lower mantle. Earth and Planetary Science Letters, 434. pp. 264-273. ISSN 0012-821X
Abstract
Fe and Al are two of the most important rock-forming elements other than Mg, Si, and O. Their presence in the lower mantle’s most abundant minerals, MgSiO3 bridgmanite, MgSiO3 post-perovskite and MgO periclase, alters their elastic properties. However, knowledge on the thermoelasticity of Fe- and Al-bearing MgSiO3 bridgmanite, and post- perovskite is scarce. In this study, we perform ab initio molecular dynamics to calculate the elastic and seismic properties of pure, Fe3+- and Fe2+-, and Al3+-bearing MgSiO3 perovskite and post-perovskite, over a wide range of pressures, temperatures, and Fe/Al compositions. Our results show that a mineral assemblage resembling pyrolite fits a 1D seismological model well, down to, at least, a few hundred kilometers above the core-mantle boundary, i.e. the top of the D′′ region. In D′′, a similar composition is still an excellent fit to the average velocities and fairly approximate to the density. We also implement polycrystal plasticity with a geodynamic model to predict resulting seismic anisotropy, and find post- perovskite with predominant (001) slip across all compositions agrees best with seismic observations in the D′′.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015, Elsevier. This is an author produced version of a paper published in Earth and Planetary Science Letters. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Lower mantle; pyrolite; bridgmanite; post-perovskite; elastic properties; first-principles |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number NERC NE/K006290/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 20 Nov 2015 10:14 |
Last Modified: | 05 Nov 2017 20:05 |
Published Version: | http://dx.doi.org/10.1016/j.epsl.2015.11.030 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.epsl.2015.11.030 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:92113 |