Thermal response of the mantle following the formation of a “super‐plate”

Abstract

Evidence indicating that the mantle below Pangea was characterized by elevated temperatures supports the widely held view that a supercontinent insulates the underlying mantle. Implementing a 3D model of mantle convection featuring distinct oceanic and continental plates, we explore different effects of supercontinent formation on mantle evolution. We find that a halt in subduction along the margins of the site of the continental collision is sufficient to enable the formation of mantle plumes below a composite “super‐plate” and that the addition of continental properties that contribute to insulation have little effect on sub‐continental temperature. Our findings show that the mean temperature below a supercontinent surpasses that below the oceanic plates when the former is a perfect insulator but that continental thermal insulation plays only a minor role in the growth of sub‐supercontinent mantle plumes. We suggest that the growth of a super‐oceanic plate can equally encourage the appearance of underlying upwellings.