The Generation of Plate Tectonics from Mantle Dynamics

Abstract

This chapter surveys the relation between mantle dynamics and plate tectonics, from the perspective that the plates are the surface manifestation, that is, the top thermal boundary layer, of mantle convection. Simple thermal convection explains some features of plate tectonics: that is, plate forces, like slab pull and ridge push, are convective forces; the seafloor structure is typical of thermal boundary layers; and slab and plume fluxes are characteristic of internally heated convection. There are, however, many aspects of plate tectonics that are poorly explained by simple convection theory; for example, the generation of platelike strength distributions and plate boundaries requires more complex lithospheric rheological mechanisms. Indeed, the formations of convergent, divergent, and strike-slip margins are all uniquely enigmatic, and each requires special consideration. The physics of plate generation and plate boundary formation through self-weakening feedback mechanisms, such as grain damage and melting, are some of the key developments for understanding the generation of plate tectonics from mantle convection on Earth and other planets.