Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9522525 | Earth and Planetary Science Letters | 2005 | 10 Pages |
Abstract
Using elastic constants determined by ab initio molecular dynamics over a range of temperatures, we show that the seismic anisotropy of MgSiO3 perovskite is significantly temperature dependent. At 90 GPa, the direction of greatest shear wave splitting changes from [001] at 0 K to [010] at 3500 K. In addition, there is no shear wave splitting in the [100] direction at 0 K, but a significant amount of splitting is exhibited at 3500 K. We have also calculated the first set of high-temperature elastic constants of the new post-perovskite phase by ab initio molecular dynamics methods. We find that, in contrast to MgSiO3 perovskite, temperature has little effect on the acoustic anisotropy of this phase. We determine âln VS/âln VP for the post-perovskite phase and find it to be very low, about 0.9. This may be an important parameter for mapping out the post-perovskite phase in the lowermost mantle.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth and Planetary Sciences (General)
Authors
Stephen Stackhouse, John P. Brodholt, J. Wookey, J.-M. Kendall, G. David Price,