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Thermoelastic Properties of MgSiO3-Perovskite: Insights on the Nature of the Earth’s Lower Mantle

R. M. Wentzcovitch, B. B. Karki, M. Cococcioni, and S. de Gironcoli
Phys. Rev. Lett. 92, 018501 – Published 9 January 2004
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Abstract

We have determined by means of first principles quasiharmonic calculations the elastic constants and acoustic velocities of MgSiO3 perovskite, the most abundant mineral of the Earth’s lower mantle (LM), at pertinent pressures and temperatures. Using these results, along with the effects of low concentration iron alloying and the thermoelasticity of the most important secondary LM phase, MgO, we predict the isotropic elastic moduli of likely LM aggregates. Comparison with seismic values extracted from the preliminary reference Earth model indicates that the top of the LM behaves as a typical aggregate of pyrolitic composition, likewise the upper mantle. But systematic deviations that cannot be accounted for by alterations in the geotherm alone develop toward the deep LM. This result could be viewed as evidence in support of radially inhomogeneous LM models.

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  • Received 14 April 2003

DOI:https://doi.org/10.1103/PhysRevLett.92.018501

©2004 American Physical Society

Authors & Affiliations

R. M. Wentzcovitch1,2, B. B. Karki3, M. Cococcioni2, and S. de Gironcoli2

  • 1Department of Chemical Engineering and Materials Science, Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA
  • 2Scuola Internazionale Superiore di Studi Avanzati (SISSA) and INFM-DEMOCRITOS National Simulation Center, I-34014 Trieste, Italy
  • 3Department of Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803, USA

See Also

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Phys. Rev. Focus 13, 1 (2004)

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Vol. 92, Iss. 1 — 9 January 2004

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