The proposed work will develop and use models of mantle flow and convection to understand the state and evolution of the solid earth. The work will include studies of mantle plumes and hotspots; plumes provide an indicator of mantle flow throughout the depth of the mantle, and recent seismic observations of plumes will allow a direct comparison of models of mantle flow with observation of plumes that are moved and distorted by mantle flow. These results will also be important for understanding hotspot tracks and plate motions, as well as flow in the mantle. The work will also address the motions of subducted material and other heterogeneities in the mantle, and will relate them to geochemical signatures of heterogeneity in the mantle. This will build upon recently developed statistical models of the development and evolution of mantle heterogeneity, and will provide a means of relating observed geochemical evidence of heterogeneity with dynamical processes in the mantle. Further development of flow and convection models will be done to deal more realistically with thermal convection and mantle rheology. Recent developments for inversion of models will be applied in order to better constrain our conclusions. Since the models predict a range of geophysical phenomena (including the geoid, plate motions, polar wander) the results of the model studies will be systematically applied to these other phenomena.
The work will relate the dynamic processes of flow and convection to the emerging seismological pictures of mantle structure, as well as to the geochemical evolution of the Earth. This will allow a more unified view of the workings of the Earth's interior on both short and long time scales. The work will involve the training of graduate students, and will also develop numerical models that will be available to other researchers. The results of the work will have broad implications for understanding the dynamics and evolution of the Earth, and will relate dynamical, tectonic and geochemical views of the evolution and working of the Earth system, which represents an extremely active area of earth science research.
