Paper No. 3
Presentation Time: 8:30 AM
Plate Boundary Evolution and Mantle Plume Eruptions during the Last Billion Years
The convective engine that drives the plates is composed of two major components: 1) cold lithospheric slabs sink back into the mantle in subduction zones, and 2) hot material rising from the core mantle boundary in the form a of mantle plumes (hot spots). Plate motions are driven primarily by the negative bouyancy of the subducting slab (slab pull, ~70%), the horizontal component of gravity that acts perpendicular to the mid-ocean ridge axes (ridge push, ~20%), and the entrainment of the deep roots of the continental lithosphere in the upper mantle (mantle drag, ~10%). The motions of the lithosphere, together with initiation of mantle plumes, provides the major boundary conditions that constrain the evolving pattern of convection in the deep Earth. In order to model the pattern of mantle convection during the last 1000 million years, it is necessary to construct a global, plate tectonic model that describes the continuous evolution of plate boundaries and the sporadic occurrence of mantle plumes. In this paper we present an animation that illustrates: 1) the evolution of plate boundaries since the early Neoproterozoic (1200 Ma), and the location and timing of mantle plume eruptions.