On mantle drag force for the formation of a next supercontinent as estimated from a numerical simulation model of global mantle convection

摘要

Three-dimensional spherical mantle convection was simulated to predict future continental motion and investigate the driving force of continental motion. Results show that both the time required (>= 300 Ma from the present) and the process for the next supercontinent formation are sensitive to the choice of critical rheological parameters for mantle dynamics, such as a viscosity contrast between the upper and lower mantles and a yield strength of the lithosphere. From all the numerical models studied herein, mantle drag force by horizontal mantle flow beneath the continents may mostly act as a resistance force for the continental motion in the process of forming a new supercontinent. The maximum absolute magnitude of the tensional and compressional stress acting at the base of the moving continents is in the order of 100 MPa, which is comparable to a typical value of the slab pull force.