How did the foreland react? Yangtze foreland fold-and-thrust belt deformation related to exhumation of the Dabie Shan ultrahigh-pressure continental crust (eastern China)

During the Triassic collision of the Yangtze and Sino-Korean cratons, the l eading edge of the Yangtze crust subducted to mantle depths and was subsequ ently exhumed as a penetratively deformed, coherent slab capped by a normal shear zone. This geometry requires a reverse shear zone at the base of the slab, and we suggest that the Yangtze foreland fold-and-thrust belt consti tutes this zone. Lower Triassic rocks of the eastern foreland record NW-SE compression as the oldest compressional stress field; onset of related defo rmation is indicated by Middle Triassic clastic sedimentation. Subsequent J urassic stress fields show a clockwise change of compression directions. Ba sed on nearly coeval onset and termination of deformation, and on a common clockwise change in the principal strain/stress directions, we propose that the foreland deformation was controlled by the extrusion of the ultra high -pressure slab. Widespread Cretaceous-Cenozoic reactivation occurred under regional extension to transtension, which characteristically shows a large- scale clockwise change of the principal extension directions during the Low er Cretaceous.