Forward and Inverse Models of Coupled Plate Tectonics and Mantle Convection using Data Assimilation

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In this project, we will study the forces that drive plate tectonics and continental drift. Plate tectonics is the surface expression of thermal convection, representing the overall process by which the earth acts as a giant heat engine. A basic understanding of mantle convection contributes to understanding processes that control natural hazards (great earthquakes) and the occurrence of oil (within deep, offshore sedimentary basins). In this project, we will develop sophisticated computer models that resolve the forces driving and resisting plate tectonic motions. The models will assimilate some data sets (meaning that they will be input as constraints) and then they will be tested by independent data. On a global scale, the models will be the most sophisticated (in terms of both resolution and physics) attempted by any group internationally. To achieve the resolution required, we may use the largest computers that NSF is now installing. An important impact of the project will be the training of two Ph.D. students in geophysics. They will gain enormous experience with sophisticated numerical methods, supercomputing technologies, and the linkage of data with numerical models, especially the linkage between earth dynamics and sedimentary basin evolution. These skill sets are important for scientists needed by international oil companies in their search for oil in deep sedimentary basins.In our research, we link plate motions, mantle structure, and vertical motions with forward and inverse numerical models. The research will require a greater level of data integration than can now be achieved with a combination of software we have developed. This research involves three closely applied topics. First, it involves the prediction of global plate motions as a function of time, using highly resolved finite element models in which the variable viscosity of the plate margins, slabs, and mantle wedges are accounted for. Second, it involves the prediction of global (eustatic) and relative sea level changes using a new paleogeography-mantle convection system that we have developed. Third, it involves further development and application of inverse and adjoint models using seismic tomography, dynamic topography constraints, and plate motions.