Palaeo-stress fleld and tectonic evolution of the Mazhan graben area in the Yi-Shu fault zone of the Tan-Lu fault belt, East China

The Mazhan graben is located in the Yi-Shu fault zone, which is the middle segment of the Tan-Lu fault belt, one of the oldest and famous large fault belt in China. As a result of the structural analyses on the change of stress field and basin formation, it is clarified that tectonic evolution of the Manzhan graben can be divided into three stages, namely the pre-graben first stage in Palaeozoic to middle Jurassic, the graben-forming second stage in Cretaceous and the post-graben third stage in post-Palaeogene. Palaeo-stress field and tectonic movement have also changed from NW-SE compressive state resulted in thrusting with sinistral shear movement at the first stage, through NNE-SSW compressive state that formed "graben/horst/graben" as the final tectonic framework at the second stage, to NNW-SSE compression with sinistral shearing and rising of the area at the third stage. The fundamental dynamics of these large scale fault movement in East China would be affected by Kular palaeo-plate, however its precise study is problem in the future