The phase equilibria, structures, and properties of a high-pressure polymorph of silicate perovskite, called post-perovskite, are discussed. This phase was discovered in 2004 and provides a viable candidate for a deep mantle phase transition in the primary lower mantle mineral, silicate perovskite. Post-perovskite may exist in regions of the lowermost mantle at temperatures below about 3,000. K, and the phase transition from perovskite to post-perovskite may explain observations of a velocity discontinuity in seismic S waves and relatively strong anisotropy of the lower most mantle D" region. The phase transition has important dynamical consequences for heat transport and boundary layer instabilities.
|Original language||English (US)|
|Title of host publication||Mineral Physics|
|Number of pages||31|
|State||Published - Jan 1 2015|
Bibliographical notePublisher Copyright:
© 2015 Elsevier B.V. All rights reserved.
- Boundary layer instabilities
- Core-mantle boundary
- Core-mantle heat flux
- D" discontinuity
- D" region
- Lower mantle
- Phase transition