Plume‐Slab Interactions Can Shut Off Subduction

Abstract

AbstractMantle plumes are typically considered secondary features of mantle convection, yet their surface effects over Earth's evolution may have been significant. We use 2‐D convection models to show that mantle plumes can in fact cause the termination of a subduction zone. This extreme case of plume‐slab interaction is found when the slab is readily weakened, for example, by damage‐type rheology, and the subducting slab is young. We posit that this mechanism may be relevant, particularly for the early Earth, and a subdued version of these plume‐slab interactions may remain relevant for modern subduction zones. Such core‐mantle boundary–surface interactions may be behind some of the complexity of tomographically imaged mantle structures, for example, in South America. More generally, plume “talk back” to subduction zones may make plate tectonics more episodic.