GEODYNAMIC MODELING OF SLAB-DRIVEN MANTLE FLOW AND UPWELLING AT SLAB EDGES (Invited Presentation)

Over the past 20 years, seismic observations, geochemical constraints, and geodynamic modeling have converged on a three-dimensional framework for subduction zones. The recognition of the three-dimensional nature of the mantle flow field in subduction zones is a fundamental milestone that has significantly affected the perception and conceptualization of subduction processes and numerical modeling. This talk explores recent 3D geodynamic models of slab-driven mantle flow, including trench parallel flow, toroidal flow around slab edges, mantle upwelling at lateral slab edges, and small scale convection within the mantle wedge. In particular, the slab-driven asthenospheric flow through slab windows, slab tears, and around lateral slab edges is examined. The 3D geodynamic models show that mantle upwelling associated with the toroidal flow around slab edges typically occurs lateral to the slab edge, located within 500 km outboard of the slab edge. The slab edge driven mantle upwelling may lead to melting and volcanism that is distinct from typical arc volcanism associated with corner flow in the mantle wedge. Furthermore, the results show that regional 3D geographically referenced numerical models have the ability to spatially link the predicted slab edge related mantle upwelling with the location of observed slab derived melts, such as adakites.