Formation of the 1300-km-wide intracontinental orogen and postorogenic magmatic province in Mesozoic South China: A flat-slab subduction model

We propose a flat-slab subduction model for Mesozoic South China based on both new sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon data and a synthesis of existing structural, geochronological, and sedimentary facies results. This model not only explains the development of a broad (~1300-km-wide) intracontinental orogen that migrated from the coastal region into the continental interior between ca. 250 Ma and 190 Ma, but can also account for the puzzling chain of events that followed: the formation of a shallow-marine basin in the wake of the migrating foreland fold-and-thrust belt, and the development of one of the world’s largest Basin and Range– style magmatic provinces after the orogeny. The South China record may serve as an example of the multiple effects of fl at-slab subduction, including migrating orogenesis and foreland fl exure, synoro genic sagging behind the active orogen, postdelamination lithospheric rebound, and the development of a Basin and Range–style broad magmatic province.