Abstract

Mantle convection produces viscous stresses that warp Earth’s surface (i.e. dynamic topography). Redistribution of masses during mantle convection can also alter Earth’s moment of inertia and cause Earth’s geographic poles to shift (i.e. True Polar Wander). These mantle convection-driven processes have undoubtedly had profound effects on sea level change, landscape evolution, climate change, and biodiversity. This study aims to understand how Earth’s plate tectonic history, which exceeds >50% uncertainty by the mid-Cretaceous due to subduction, affects Earth’s mantle convection, dynamic topography and True Polar Wander. We build TOMOPAC , a plate reconstruction that adds unsubducted slabs from mantle seismic tomography for the uncertain Pacific-Panthalassan region. We incorporate TOMOPAC and a widely-used reference plate reconstruction (Matthews et al., 2016) into TERRA forward global mantle convection models to compare their predictions for Earth’s geoid, present ocean dynamic topography, and True Polar Wander. Preliminary results show TOMOPAC produces synthetic geoids that correlate ~35% closer to Earth’s long-wavelength geoid compared to the reference plate model. We discuss the implications of alternative plate tectonic histories for predicting dynamic topography and True Polar Wander.