Recent tectonic plate decelerations driven by mantle convection

Abstract

We explore recent changes in tectonic plate velocities using a model of mantle flow that is based on a new high‐resolution global tomography model derived from simultaneous inversions of global seismic, geodynamic and mineral physical data sets. This plate‐coupled mantle convection model incorporates a viscosity structure that reconciles both glacial isostatic adjustment and global convection‐related data sets. The convection model successfully reproduces present‐day plate velocities and global surface gravity and topography constraints. We predict time‐dependent changes in mantle buoyancy that give rise to present‐day decelerations of several major plates, in particular the fast‐moving Pacific and Nazca plates. We verify the plausibility of these predicted plate decelerations using space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions. These plate kinematic constraints are employed to determine a new global map of present‐day plate decelerations that agree well with the mantle flow predictions.