临潭—宕昌主干断裂南东段晚第四纪活动的地质地貌证据

Geological and Geomorphological Evidence of Late Quaternary Activity along the Southeastern Segment of the Lintan—Tanchang Major Fault,China

临潭—宕昌断裂带总体上位于东昆仑断裂和西秦岭北缘断裂之间。作为甘东南构造转换和变形传递过程中的一条重要的断裂,其几何展布\,新活动性和运动特征对讨论地震的孕育有着至关重要的作用。前人对临潭—宕昌断裂进行了大量的调查和研究,尤其在2013年岷县—漳县MS6.6地震发生后,认为该断裂各分支断裂活动差异明显,除主干断裂南东段不活动外,其余次级断裂在晚第四纪以来皆有活动。笔者通过对临潭—宕昌主干断裂1∶5万断裂活动性填图工作,在主干断裂南东段发现了多处晚第四纪活动的地质与地貌证据,这一发现对临潭—宕昌断裂带结构特征及活动性是一个重要补充,有助于完善该地区的区域构造几何图像和运动特征,对认识区域构造活动、构造转换和变形传递有关重要的意义。

The Lintan—Tanchang fault zone is located between the east Kunlun fault and the northern margin of the West Qinling fault.As an important fault in the process of tectonic transformation and deformation transfer in the southeastern Gansu,China,its geometric distribution,new activity,and movement characteristics play a crucial role in earthquake preparation.Much investigation and research on the Lintan—Tanchang fault has been conducted,especially since the occurrence of the Minxian—Zhangxian MS6.6 earthquake.It has been thought that the activities of each segment of the fault had significant differences.With the exception of the southeast section of the main fault,the remaining secondary faults have been active since the late Quaternary.In this paper,we discovered geological and geomorphological evidence of late Quaternary activities along the southeast section of the Lintan—Tanchang main fault.As an important supplement of the structural features and activities of this fault,this discovery can help perfect the geometric images and motion characteristics of the regional structure,and it is vital in understanding the regional tectonic activities,tectonic transformation,and deformation transfer.