Plate tectonics, mixed heating convection, and the divergence of mantle and plume temperatures

Abstract

Abstract Petrological data indicate that upper mantle and mantle plume temperatures diverged 2.5 b.y. ago. This has been interpreted as plate tectonics initiating at 2.5 Ga, with Earth operating as a single-plate planet before that time. We took an Occam’s razor view and hypothesized that the continuous operation of plate tectonics can explain the divergence. We validated this hypothesis by comparing petrological data to results from mixed heating mantle convection models in a plate-tectonic mode of mantle cooling. The comparison shows that the data are consistent with plate tectonics operating throughout geologic history.