Craton Deformation from Flat-Slab Subduction and Rollback

The mechanisms underlying the deformation and eventual destruction of Earth's cratons remain enigmatic, despite proposed links to subduction and deep mantle plume processes. Here, we study the deformation of the North China Craton using four-dimensional mantle flow models of the plate–mantle system since the late Mesozoic, integrating constraints from lithospheric deformation, mantle seismic tomography, and the evolution of surface topography. We find that flat-slab subduction induced landward shortening and lithospheric thickening, while subsequent flat-slab rollback caused seaward extension and lithospheric thinning. Both subduction phases resulted in substantial topographic changes in basin sediments. Rapid flat-slab rollback, coupled with a viscosity jump and phase change across the 660-km mantle discontinuity, was a key ingredient in shaping a large mantle wedge. We argue that craton deformation through lithospheric extension and thinning was triggered by the subduction of a flat slab and its subsequent rollback. The integration of data into mechanical models provides insights into the four-dimensional dynamic interplay involving subduction, mantle processes, craton deformation, and topography.