Middle-late Mesozoic tectonic evolution of the NE China—corresponding to westward subduction of the paleo-Pacific plate

How did the continent-oceanic plate interact, and when did the initial west paleo-Pacific plate subduction beneath Eurasian continent occur, are still unknown. NE China deformation, volcanic eruptions and magmatic intrusions can give some constraints. Muling located in the Dunhua-Mishan fault zone in NE China, is a key area where the E-W-trending Eurasian domain changed to NE-trending west Pacific Plate domain in NE China. During the Mesozoic time, at least three stages of deformation occurred, including: (1) E-W-trending structures with extensive ductile shear deformation and south-verging folds which result from thrusting towards the south, followed the emplacement of granitic rocks. (2) NE- or NNE-trending thrust faults and strike-slip movement, accompanied by the formation of west-verging inclined and recumbent folds. This phase deformation changed the whole tectonic framework of eastern China from an E-W-trending Eurasian domain to a NE-trending west Pacific Plate domain. (3) NE-trending strike-slip faults and E-W-trending strike-slip motion. Field investigations of Mesozoic ductile shear zone and faults, granitic intrusions and dykes, combined with zircon U-Pb dating and muscovite ⁴⁰Ar/³⁹Ar plateau ages, reveal the age of the E-W-trending structures as ~254-209Ma, and NE–SW-trending tectonic belts as ~182–170 Ma. The tectonic transformation of the eastern China continent involved a change from E-W to NE-SW-trending structures was a response to the initial subduction of paleo-Pacific plate.