Early Mesozoic intracontinental deformation in the eastern North China Block: Implication for an indentation model of North China to South China blocks

Abstract

The Qinling‐Dabie‐Sulu Orogen was formed by the collision of the North and South China blocks during the Indosinian Period. The intracontinental deformation was subsequently developed during the Late Triassic to Early Jurassic in the northeastern, eastern, and southeastern parts of eastern North China Block with different structural patterns. In this paper, we present structural analysis of the Indosinian deformation in the western Shandong and southern Liaoning provinces and synthesized the previous studies of the Triassic‐Early Jurassic deformation in different areas of the eastern North China Block, from the northeastern, central to southeastern parts. Integrating the previous studies of petrology, geochronology, and geophysics, we suggested that (1) a series of top‐to‐the‐northwest thrust‐nappes were formed in the Sulu Orogen, and the southeastward antithetic faults developed in the South China Block. In the eastern North China Block, the Indosinian intracontinental deformation is intensely developed near the orogenic belt as thrust‐nappes and away from the belt developed open folds. (2) The present‐day structural lines in the northeastern, central, and southeastern parts of eastern North China Block show the S‐N‐, E‐W‐, and NE‐trending lines, respectively. It could be the structural response to the dynamics of an orocline or indentation induced by Triassic collision of the North and South China blocks; (3) the eastern margin of the North China Block subducted southeastward beneath the South China Block along the Wulian‐Qingdao‐Yantai Fault during the Indosinian Period.