Yellowstone Plume Drives Neogene North American Plate Motion Change.

Plate motion changes provide powerful constrains on plate tectonic forces. North America is ideal to explore these forces. We use recently published high‐temporal resolution plate reconstructions of North America, which reveal a velocity slow‐down at ∼17 Ma, roughly coeval with the eruption of the Yellowstone plume, together with a stratigraphic analysis of hiatus surfaces across the continent, which provides proxy information for paleotopography. Using a simple Couette/Poiseuille flow models we estimate asthenosphere flow beneath North America and its impact on Neogene plate motion. We find that North America's Neogene plate motion change can be explained by Poiseuille flow in the asthenosphere generated upon the arrival of the Yellowstone plume and that the flow length‐scale matches the extent of hiatus surfaces. While plume driven upper mantle flow constitutes a geodynamically viable model to explain North America's Neogene plate motion change it provides an intrinsic link between vertical and horizontal plate motions. Plain Language Summary: Plate motion changes are increasingly well documented in the geologic record. However, the underlying forces that initiate these plate motion changes remain poorly understood. Over the past years a pressure driven, so‐called Poiseuille flow, model for upper mantle flux in the asthenosphere has gained increasing geodynamic attention–for a number of fluid dynamic arguments. This elegantly simple model makes a powerful testable prediction: Plate motion changes should coincide with regional scale mantle convection induced elevation changes. The latter are best inferred for continents from stratigraphic evidence. In this study we analyse newly available constrains on the Neogene kinematic plate history of North America together with a novel stratigraphic frame‐work based on the principle of hiatus analysis. The stratigraphic frame work provides proxy information for paleo elevation. Combining these newly available constrains we show for the first time that: (a) Poiseuille flow induced by the arrival of the Yellowstone hotspot provides a compelling explanation for the observed coeval velocity and topographic change of North America, and (b) the Yellowstone plume push force is sufficient to initiate a plate motion change of North America under considerations of a quantitative geodynamic force balance analysis. Key Points: We analyse the Neogene kinematic plate history of North America together with a stratigraphic frame‐work base on the principle of hiatusPoiseuille flow model links changes in dynamic topography and plate motion changes via a geodynamically plausible modelYellowstone plume provides a dynamically viable mechanism to drive Neogene North America platemotions [ABSTRACT FROM AUTHOR]