Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4742486 | Physics of the Earth and Planetary Interiors | 2009 | 7 Pages |
Abstract
Ab initio quantum mechanical computations suggest that potassium (K) preferentially partitions into MgSiO3 perovskite (pv) over post-perovskite (ppv) under lower mantle conditions when charge coupled with trivalent cations of aluminum (Al3+) or iron (Fe3+). In an Al-bearing MgSiO3, the equilibrium constant KD increases with pressure, leveling off at ∼33 at ∼100 GPa and 3000 K. For an Fe-bearing MgSiO3, KD slowly increases with pressure reaching a value of ∼8 at core-mantle boundary (CMB) pressures and 3000 K. Our results imply that a potassium-enriched lowermost mantle layer based on the stability of ppv is unlikely.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geophysics
Authors
Kanani K.M. Lee, Gerd Steinle-Neumann, Sofia Akber-Knutson,