Title: The Middle–Late Triassic fold–thrust belt on Liaodong Peninsula, North China Block: Implication for propagation of the Sulu orogeny toward the NE
Abstract: Processes related to the subduction of the South China Block beneath the North China Block and collision of the two blocks along the Qingling–Dabie–Sulu Orogenic Belt have been well studied. Different tectonic models have been proposed based on time constraints of metamorphism and magmatism and the uplift and exhumation of the HP–UHP metamorphic belt. However, propagation of the foreland thrust belt during the collision along the eastern North China Block has not been well documented, leading to a weak understanding of the collision process. The Liaodong Peninsula, 200–300 km northeast of the Sulu Orogenic Belt, is an essential area for the study of the foreland thrust belt. The rocks of the peninsula record at least three deformation events during the Mesozoic: D1 NW–SE folds and thrust faults that were strongly overprinted by D2 NE–SW thrusts and folds and D3 large-scale regional extensional structures. According to detailed geological investigation and tectonic stress reconstruction using striations and dolomite twins, seven imbricate fold–thrust units in the Pulandian, Guiyunhua and Qingchengzi areas of Liaodong Peninsula were defined as representing the D1 deformation. Together with thrust units in the southernmost part of Liaodong Peninsula and on the northern Jiaodong Peninsula, a top-to-the-NE propagated fold–thrust belt is proposed for the eastern North China Block. UPb ages of zircons from three post-tectonic dyke samples in the Qingchengzi area, combined with previous geochronological results, constrain the D1 deformation at 249–224 Ma. We suggest that the collision of the South China and North China blocks along the Sulu Orogenic Belt and the subduction of the South China Block beneath the North China Block resulted in NE–SW compression, formation of a detachment fault in the deep crust, and propagation of a fold–thrust belt toward the NE in the upper plate along the eastern margin of the North China Block.
Publication Year: 2023
Publication Date: 2023-03-15
Language: en
Type: article
Indexed In: ['crossref']
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