Abstract

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, 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.