Effects of continental insulation and the partitioning of heat producing elements on the Earth's heat loss

Continental lithosphere influences heat loss by acting as a local insulator to the convecting mantle and by sequestering heat-producing radioactive elements from the mantle. Continental heat production can have a two-part effect since it decreases the amount of internal heat driving convection, which lowers mantle temperature, while also increasing the local insulating effect of continental lithosphere, which raises mantle temperature. We explored these competing effects using simulations that incorporated enriched continents within a mixed internal- and bottom-heated convecting mantle. Increasing continental surface area was found to enhance global heat loss for a range of heat production distributions and Rayleigh numbers. The effect of enriched continents was evident as a double peak in the continental surface area values that maximize global heat loss. That the presence of continental lithosphere could increase average mantle temperature despite the mantle being depleted suggests that continents can significantly influence mantle potential temperature.