Emergence of Plate Tectonics from Mantle Dynamics: From Grains to Planetary Scales

The emergence of plate tectonics from mantle convection is a defining moment in Earth evolution. The physics governing the developed tectonic plates relies on the behavior of mineral grains about 1mm in size. Deformation and damage tend to reduce grains and cause weak zones that lead to focused plate boundaries, while grain damage and comminution compete against grain-growth, which heals weak zones. This talk will give an overview of how accumulation of grain damage on weak zones in the cooler Earth may have allowed global plate tectonics to slowly emerge during the early Archean.