Plate tectonics and surface environment: Role of the oceanic upper mantle

Earth is so far the only planet that exhibits plate tectonics, and along with the right heliocentric distance and the presence of surface water, plate tectonics is among necessary conditions for a habitable planet. Yet, the physics of this particular style of mantle convection is poorly understood, creating a substantial bottleneck in developing the general theory of planetary evolution. As plate tectonics is characterized by the subduction of oceanic lithosphere, a better understanding of the oceanic upper mantle could potentially help to break this stalemate. In this review, I summarize available theoretical, observational, and experimental constraints on the evolution of the oceanic upper mantle and its rheology, place the study of the oceanic upper mantle in the big picture of Earth evolution, and provide some suggestions for future research in relevant disciplines, including marine geophysics and computational geodynamics.