Cenozoic asthenospheric flow history in the Atlantic realm: Insights from Couette/Poiseuille flow models

Mantle convection is an essential component of the Earth system. Yet its history is not well known , in part, as the strength of tectonic plates conceals the underlying flow. To date, global mantle convection models have reached an impressive level of sophistication due to significant advancement of computational infrastructures and numerical techniques. This ultimately allows geodynamicists to reconstruct past mantle states through using, for instance, inverse geodynamic models based on adjoint equations. However, key input parameters of these models --- such as thermo-chemical flow properties and rheology --- are complex and poorly known. This in turn limits their ability to effectively interpret the reconstructed mantle flow, thus motivating one to pursue an approach that aims to conceptualize paleo-mantle-flow at a simple analytical level.

To this end, the existence of thin, mechanically weak asthenosphere permits one to develop an analytical Couette/Poiseuille model of asthenospheric flow, where flow is associated with moving tectonic plates, and with lateral pressure gradients due to rising plumes and sinking slabs. Here we present estimates of the Cenozoic asthenospheric flow history from such models in the Atlantic realm. We, moreover, link them to azimuthal seismic anisotropy as well as mantle flow retrodiction simulated by inverse geodynamic models. Our analytically derived asthenospheric flow indicates that it is in broad agreement with the orientation of seismic azimuthal anisotropy, and with the large-scale flow patterns from mantle flow retrodictions. In light of these results, our study suggests exploiting a hierarchy of geodynamic models together with growing observational constraints on mantle flow induced surface expressions to gain a better understanding of paleo-mantle-flow.