The elasticity of the MgSiO3 post-perovskite phase in the Earth's lowermost mantle

T. Iitaka, K. Hirose, K. Kawamura, M. Murakami

Research output: Contribution to journalArticle

232 Citations (Scopus)

Abstract

MgSiO3 perovskite has been assumed to be the dominant component of the Earth's lower mantle, although this phase alone cannot explain the discontinuity in seismic velocities observed 200-300 km above the core-mantle boundary (the D″ discontinuity) or the polarization anisotropy observed in the lowermost mantle. Experimental and theoretical studies that have attempted to attribute these phenomena to a phase transition in the perovskite phase have tended to simply confirm the stability of the perovskite phase. However, recent in situ X-ray diffraction measurements have revealed a transition to a 'post-perovskite' phase above 125 GPa and 2,500 K-conditions close to those at the D″ discontinuity. Here we show the results of first-principles calculations of the structure, stability and elasticity of both phases at zero temperature. We find that the post-perovskite phase becomes the stable phase above 98 GPa, and may be responsible for the observed seismic discontinuity and anisotropy in the lowermost mantle. Although our ground-state calculations of the unit cell do not include the effects of temperature and minor elements, they do provide a consistent explanation for a number of properties of the D″ layer.

Original languageEnglish
Pages (from-to)442-445
Number of pages4
JournalNature
Volume430
Issue number6998
DOIs
Publication statusPublished - Jul 22 2004
Externally publishedYes

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Elasticity
Anisotropy
Temperature
Phase Transition
X-Ray Diffraction
Theoretical Models
perovskite

ASJC Scopus subject areas

  • General

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Iitaka, T., Hirose, K., Kawamura, K., & Murakami, M. (2004). The elasticity of the MgSiO3 post-perovskite phase in the Earth's lowermost mantle. Nature, 430(6998), 442-445. https://doi.org/10.1038/nature02702

The elasticity of the MgSiO3 post-perovskite phase in the Earth's lowermost mantle. / Iitaka, T.; Hirose, K.; Kawamura, K.; Murakami, M.

In: Nature, Vol. 430, No. 6998, 22.07.2004, p. 442-445.

Research output: Contribution to journalArticle

Iitaka, T, Hirose, K, Kawamura, K & Murakami, M 2004, 'The elasticity of the MgSiO3 post-perovskite phase in the Earth's lowermost mantle', Nature, vol. 430, no. 6998, pp. 442-445. https://doi.org/10.1038/nature02702
Iitaka, T. ; Hirose, K. ; Kawamura, K. ; Murakami, M. / The elasticity of the MgSiO3 post-perovskite phase in the Earth's lowermost mantle. In: Nature. 2004 ; Vol. 430, No. 6998. pp. 442-445.
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