Strong chemistry dependence of the perovskite - post-perovskite phase transition boundary and of the post-perovskite structure
Abstract
We show that MgSiO3 of representative mantle composition transforms to the post-perovskite structure at a noticeable lower pressure than pure MgSiO3. We also show that there is a further transition to a different post-perovskite than previously reported. Together, they indicate that minor-element chemistry, in particular the presence of Al, is highly influential on structure and stability of post-perovskite phases and puts constrains on rock composition and temperature profile in the Earth's lowermost mantle. We further present the first Raman spectrum of a post-perovskite phase which indicates a strong polarized bonding between the Mg- and the silicate-sublattice.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFMMR22A..06T
- Keywords:
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- 3620 Crystal chemistry;
- 3924 High-pressure behavior;
- 1645 Solid Earth