Post-Perovskite: Ten Years After - Theoretical Insights into its Physical Properties

Abstract:

The discovery in 2004 of the perovskite to post-perovskite phase transition in MgSiO₃provided an explanation for many of the usual seismic features observed at the base of the lower mantle: the frequent detection of a discontinuity a few hundred kilometres above the core-mantle boundary, seismic anisotropy and the anti-correlation of bulk and shear velocity anomalies. The full impact of the phase transition has enfolded over subsequent years, as experimental and theoretical studies have provided information on the physical properties of the perovskite and post-perovskite phases. These have aided the interpretation of seismic observations and provided input for dynamical models.

Here we review progress in determining the properties of the perovskite and post-perovskite phases at lower mantle conditions, with particular attention given to the results of theoretical mineral physics studies. Our focus will be on the phase boundary, elastic properties and transport properties. The influence of impurities will also be considered. Implications for the structure, composition and dynamics of the mantle will be discussed in each case.