Eastward tectonic migration and transition of the Jurassic-Cretaceous Andean-type continental margin along Southeast China

A Mesozoic Andean-type active continental margin is believed to have developed along the Southeast China continental margin, which has been investigated in detail. However, the architecture and evolution of its retroarc-arc-forearc system, which is important for us to understand the interaction or connection between continental and oceanic lithospheres, are ambiguous. Using multiple disciplinary data comprising seismic profiles, field observations and numerical paleo-topographies, this study synthetically focused on the Jurassic-Cretaceous evolution and geodynamics of the Andean-type Southeast China continental margin. Subduction of the paleo-Pacific Plate was initiated during the Early Jurassic (~200 Ma), generating a NNE-striking Jurassic magmatic arc along the East China Sea, bounded by imbricate thrust faults on both sides and coinciding with a paleo-topographic coastal mountain range. While the Jurassic arc erupted along an ENE-striking Triassic suture zone in the northern South China Sea, dominated by the Tethyan tectonic domain and overprinted by the Pacific tectonic domain. The Jurassic coastal mountain range began to collapse and transited into a rift basin at ~135 Ma and then the Andean-type continental margin gradually switched to the western Pacific-type during the Late Cretaceous (100–72 Ma), accompanied by Jurassic thrust faults inverting into Cretaceous detachment faults and magmatic arc migrated eastward to the Taiwan-Rukyu areas. Such eastward tectonic migration and transition is associated with the eastward retreat of the subducted paleo-Pacific slab. Then a regional latest Cretaceous (72–66 Ma) compression prevailed Southeast China, probably related to “ridge subduction” when the Pacific Plate replaced the paleo-Pacific Plate to subduct beneath East Asia.