Continental flooding and mantle-lithosphere dynamics

Abstract

The flooding of continental platforms is controlled as much by global eustatic sea level fluctuations as by epeirogenic, vertical motions. This basic, but underappreciated, geologic observation is consistent with the simplest model of mantle convection. Eustatic fluctuations are driven by changes in the top thermal boundary layer of convection (the lithosphere}, while epeirogenic motions are driven by convective upwellings and downwellings (subduction). Continental platforms were exposed during the Triassic before Pangea broke apart and then became flooded during the Cretaceous when the continents were dispersing. This longest term cycle in global sea level is predicted by models of mantle convection where non-subducting continental plates dynamically interact with the mantle. These dynamic models predict that apparent eustatic sea level changes can be driven by long wavelength dynamic topography.