摘要
The Yinchuan Basin has undergone poly-phase subsidence along its boundary faults since the Cenozoic,and the kinematic characteristics of the boundary faults present the records of the Cenozoic evolution history of the Yinchuan Basin.On the basis of detailed measurement of the slip vector from the boundary faults of the Yinchuan Basin,together with regional structural analysis and superimposed deformation analysis,we propose that the Yinchuan Basin has been controlled by three-stage stress fields in the order of NW SE extension,NE SW extension and NE SW compression.Combined with the regional structural evolution,sedimentary sequences and geochronology,this paper suggests that the Yinchuan Basin has undergone a three-stage depression since the Cenozoic.Firstly,the NW SE extension resulted in intensive normally faulting and the occurrence of the Yinchuan Basin during the Eocene Miocene;secondly,the boundary faults are characterized by left strike-slip movement,and the Yinchuan Basin is marked by a successive depression due to the NE SW extension in the Pleistocene;lastly,the stress field transformed into the NE SW compression from NE SW extension since the Late Pleistocene,leading to the dextral movement of the boundary faults and an intensive trans-depression in the Yinchuan Basin.