9706210 O'Connell The proposed research is to study flow and thermal convection in the mantle. The work will involve thermal convection calculations for a spherical Earth model that incorporates the geometry and motions of lithospheric plates and is constrained by seismic tomographic models of mantle heterogeneity. The changes of plate geometry and motions over the last 150 My, and the evolution of the internal heterogeneity and thermal fields are also included in the model. The work extends recent mantle flow models that predict the motions of mantle plumes and hot--spots and resolve some problems with plate motions. The models also predict the motion of the rotation axis, which compares well with paleomagnetic observations of polar wander. The current work will incorporate thermal convection effects into the models. This will constitute a self consistent dynamic investigation of plumes, hotspots, the geoid, and forces on lithospheric plates. ***
