Evaluating the contribution of plate boundary forces and mantle flow on the late Cenozoic North American plate motion history with coupled global models of mantle and lithosphere dynamics

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Plate motion changes hold powerful constraints on the driving and resisting forces of tectonic plates. Here I propose to use global coupled models of the mantle and lithosphere dynamics, capable of representing plate boundary as well as mantle convection related forces, to exploit the fact that the Neogene velocity of North America relative to Nubia and Eurasia has beenmapped recently at high temporal resolution, revealing two abrupt slowdowns at 15 Ma and 7 Ma, respectively. I will combine this information with geologic indicators on the Cenozoic uplift history of western North America. The data-driven modeling approach will allow me to test whether forcing from ridge push and large scale mantle flow is sufficient to explain theNorth American plate motion change, or whether the Neogene arrival of the Yellowstone hotspot may have contributed to it, by imparting substantial sublithospheric stresses through pressure-driven (i.e., Poiseuille) upper mantle flow. The proposed work builds on earlier experience indicating that the sub-Pacific asthenosphere features a significant component of Poiseuille flow, and offers the exciting possibility to explain the North American plate motion change quantitatively through geodynamic modeling, thus helping to elucidate the force balance of a major tectonic plate.