祁连山活动断裂带中东段冷龙岭断裂滑动速率的精确厘定

Determination of the Slip Rate of the Lenglongling Fault in the Middle and Eastern Segments of the Qilian Mountain Active Fault Zone

冷龙岭活动断裂是青藏高原东北缘祁连山断裂带的重要组成部分,位于祁连山断裂带中东段。根据野外考察结果认为,该断裂全新世以来活动强烈,主要表现为左旋走滑运动,并伴有正倾滑性质,断错地貌特征明显。通过高分辨率SPOT卫星数字影像和大比例尺航空照片处理确定断层的位置,利用断错地貌测图、热释光(TL)和碳十四(14C)测年方法,厘定了冷龙岭断裂的晚第四纪滑动速率,冷龙岭断裂晚更新世以来的平均水平滑动速率为(4.3±0.7)mm/a,全新世晚期以来的平均水平滑动速率为(3.9±0.36)mm/a。

Located in the middle and eastern segments of the Qilian Mountain active fault zone, Lenglongling active fault is an important part of the Qilian Mountain fault zone in the northeastern margin of the Tibetan plateau. Based on field investigation, we found that the fault has been intensely acting since Hotocene, mainly represented by left-lateral strike slip movement with normal dip-slip, and obvious dislocated geomorphological lea tures. The location of faults was determined by processing the high resolution SPOT satellite digital images and large-scale aerial photos. Using the dislocated geomorphological plotting, thermoluminescence （TL） and carbon 14 （^11C） dating, the late Quaternary sliprate of the Lenglongling fault was accurately determined. The average horizontal slip-rate of the Lenglongling fault has been （4.3 ± 0. 7） mm / a since the late Pleistocene, and （3.9 ± 0.36） mm / a since the late Holocene.