Abstract:

Based on seismic section, DEM, historical earthquakes, dating and drilling data, this study analyzed the structural features, kinematics characteristics and genetic mechanism of Xiongpo anticline in Sichuan basin. The results can be drawn as the following aspects: (1) the space distribution of Xiongpo anticline is same with that of Pujiang-Xinjin fault zone, presenting a model of fault propagation fold and its shorten is 7.2 km with shorten rate about 30%; (2) Xiongpo anticline uplifted after (1.0±0.2) MaB.P. and it was very active in Early Pleistocene and Late Pleistocene, causing Quaternary-thickness difference between two sides of Xiongpo anticline; (3) earthquakes especially small earthquakes happening in PujiangXinjin fault zone occurred frequently and there has earthquakes history of Ms ranging from 50 to 5.9; (4) the faulting-slipping and the crushing stress from Longmenshan to Yangtze craton are the main stress mechanism of Xiongpo anticline. It can be concluded that Xiongpo anticline formation is resulted from quickly uplifting when the fault is active rather than the product of uniform stress.

Key words: Xiongpo anticline, fault propagation fold, genetic mechanism, structural feature, foreland basin