龙门山北段阳平关地区构造变形序列特征

Longmen Mountains region north deformation sequence features over Yangpingguan zone

龙门山造山带和米仓山造山带是中国大陆颇有影响力的造山带。阳平关地区位于前两者之间,阳平关断层的形成以及后期的构造变形均受这二者的明显控制和影响。通过对阳平关断层上盘、断层面以及下盘的实测研究,对阳平关地区的构造变形期次与区域构造应力场作了探讨。认为主要区域构造应力场有六期,第一期为NE-SW向挤压,第二期为NW-SE向挤压,第三期为S-N向挤压,第四期为NE-SW向挤压,第五期为NW-SE向挤压,第六期NE-SW向拉伸。阳平关地区构造变形从印支晚期一直持续到喜马拉雅期。

Yangpingguan area is located between the Longmen Mountain orogenic belt and Micang Mountain orogenic belt,which are well known as mainland of orogenic belts.The tectonic deformation of Yangpingguan faults is effected obviously by above two orogenic belts during the faults formation.Based on research on the plates and fault plane of Yangpingguan fault,tectonic deformation times and regional tectonic stress field were discussed.It is concluded that there are six tectonic stress field,such as the first period with EN-SW squeeze,the second period with NW-SE squeeze,the third period with S-N squeeze,the fourth period with EN-SW squeeze,the fifth issue period with NW-SE squeeze and the sixth period with EN-SW stretch.Tectonic deformation of Yangpingguan region continued progressed from late Indosinian to Himalayan periods.