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

Abstract

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.