Mantle-Driven Vertical Motions of the North American Continental Interior: Testing Dynamic and Isostatic Models of Long-Wavelength Uplift using the Stratigraphic Record

Mantle convection exerts a key control on a range of geological processes operating at Earth's surface, such as the generation of topography, creation of accommodation space, changes in sea-level and flooding of continental interiors. A well-known example is the North American Western Interior, where geological observations require the influence of sub-plate processes to explain the observed evolution of topography. Various geodynamic models also predict that large-scale vertical motions of the region are driven by dynamic topography. In this study, we test the predictions of dynamic topography for North America using novel databases of continental uplift. The history of vertical motions of the North American Western Interior is constrained using paleo-bathymetric markers and continental-scale sediment isopach maps. These data are used to test predictions of dynamic topography from mantle circulation models. Results show that, although the general spatial patterns of dynamic topographic change can be predicted, mantle convection models struggle to predict the amplitude of dynamic topography and the polarity of change. To investigate other possible drivers of the observed trends, geophysical constraints on properties of the present-day shallow mantle are combined with an isostatic model to explore shallow-mantle contributions to uplift in the region. Finally, we explore the uncertainty in uplift generated in the shallow mantle using a Monte Carlo error propagation.