This research is to use seismological, thermodynamic, mineral physics and experimental petrological data to infer, with error estimates, the mineralogy of the various regions of the mantle. Recent seismological work is providing high-resolution models for the radial variation, and useful resolution for lateral variation of seismic properties. The absolute values of these parameters, their gradients and their interrelationships provide data pertinent to the chemistry, mineralogy and temperature of the mantle. Two of the outstanding questions in mantle dynamics and chemistry are whether mantle discontinuities represent chemical as well as phase changes and whether the lateral variations are entirely due to temperature. Recent work on the elastic properties of perovskite and on the partitioning of Fe between perovskite and magnesiowustite will help us constrain the chemistry and thermodynamics of the lower mantle.
