Paleo-stress reconstruction and implications for the Mesozoic tectonic evolution of the Guizhong Depression, South China Block

The tectonic deformation reaction to multi-plate convergence in the northern Guizhong Depression, as well as its geodynamic process, remain poorly understood. Two phases of intracontinental deformation are identified using field geological investigations, paleo-stress inversion and seismic reflection sections: (1) early NE-SW-directed compression during the Middle Triassic to Early Jurassic; (2) later NW-SE-directed compression during the Middle Jurassic to Early Cretaceous. The reconstruction of paleo-stress provides robust constraints on the spatiotemporal evolution of stress within the Guizhong Depression. The regional SW-NE-directed compression during the Middle Triassic to Early Jurassic was driven by the collision and convergence between the Indochina and South China blocks, resulting in the formation of NW-SE-directed compressional structures during the Indosinian Period. The later SE-NW-directed paleo-stress field was probably driven by the NW-directed subduction of the Paleo-Pacific Plate during the Middle Jurassic to Early Cretaceous. The Guizhong Depression suffered two periods of compression during the Mesozoic. The early NE-SW-directed compression was caused by the collision of the Indochina and South China blocks during the Middle Triassic to Early Jurassic, but the later NW-SE-directed compression was caused by north-westward flat-slab subduction of the Paleo-Pacific Plate during the Middle Jurassic to Early Cretaceous. image