The influence of trench migration on slab penetration into the lower mantle

摘要: Abstract A two-dimensional numerical convection model in cartesian geometry is used to study the influence of trench migration on ability subducted slabs penetrate an endothermic phase boundary at 660 km depth. The transient subduction history oceanic plate modelled by imposing and motion surface. viscosity depends temperature variety styles slab behaviour found, depending predominantly velocity. When retreat faster than 2–4 cm/a, descending flattens above boundary. At slower rates it penetrates straight into lower mantle, although flattening transition zone may occur later, leading a complex morphology. can buckle, independent whether or not, especially when there localised increase Flattened are only temporarily arrested sink ultimately mantle. results offer framework for understanding revealed seismic tomography.