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Furen Xie, Institute of Crustal Dynamics,CSB (China)
Shimin Zhang, Institute of Crustal Dynamics,CSB (China)
Suqin Dou, Institute of Crustal Dynamics,CSB (China)
Xiaofeng Cui, Institute of Crustal Dynamics,CSB (China)
Saibing Shu, Institute of Crustal Dynamics,CSB (China)
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By using the calculation method of inversion of fault slip data, two stages of tectonic stress fields in the north and east margin of Qinghai-Tibet Plateau during Quaternary have been determined. It well explained the neotectonic evolution of crustal dynamic process of the Plateau. Approximately from middle or late Miocene to early Pleistocene, the tectonic stress field was characterized by a maximum principal compressional stress perpendicular to the boundary of the Plateau, and the stress regime was basically of reverse fault. The faults located in the north and east margins of the Plateau were also mainly reverse faults. Since the end of early Pleistocene, Indian Plate continues to push northward and the compressional deformation of the Plateau crust increases continuously.
Meanwhile, NW-SE direction of extension appears on the east side of the Plateau and it is favorable for the interior block of Plateau to slide towards east and southeast. It resulted that the faults located in the north and east margins of the Plateau changed from thrust to strike-slip. Then the recent tectonic stress field was formed and the stress pattern have been lasted from the end of early Pleistocene to the present. The maximum principal direction of recent tectonic stress field rotated clockwise with respect to the previous tectonic stress field, The stress regime of recent tectonic stress field is mainly of strike-slip type.
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