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GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L01304, doi:10.1029/2005GL023887, 2006

Elastic anisotropy of FeSiO3 end-members of the perovskite and post-perovskite phases

Stephen Stackhouse

Department of Earth Sciences, University College London, London, UK


John P. Brodholt

Department of Earth Sciences, University College London, London, UK


G. David Price

Department of Earth Sciences, University College London, London, UK


Abstract

The athermal elastic constants of the perovskite and post-perovskite polymorphs of pure end-member FeSiO3 were calculated from ab initio calculations. We predict that incorporating ten mole percent FeSiO3 together with four mole percent Al2O3 into MgSiO3 reduces the perovskite to post-perovskite phase transition pressure by 5 GPa. Small changes in the seismic properties of the post-perovskite phase due to the incorporation of iron and alumina are compatible with observations for the lower mantle. MgSiO3 post-perovskite enriched in fifty percent or more iron may be responsible for ultra-low velocity zones at the base of the mantle.

Received 23 June 2005; accepted 30 November 2005; published 7 January 2006.

Index Terms: 3620 Mineralogy and Petrology: Mineral and crystal chemistry (1042); 3909 Mineral Physics: Elasticity and anelasticity; 8124 Tectonophysics: Earth's interior: composition and state (1212, 7207, 7208, 8105).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 99396 bytes)

Citation: Stackhouse, S., J. P. Brodholt, and G. D. Price (2006), Elastic anisotropy of FeSiO3 end-members of the perovskite and post-perovskite phases, Geophys. Res. Lett., 33, L01304, doi:10.1029/2005GL023887.