嘉山—庐江断裂合肥盆地段第四纪活动特征初探

Preliminary study on the Quaternary activity characteristics of the Hefei Basin section of Jiashan—Lujiang fault

摘要:

嘉山—庐江断裂是郯庐断裂带安徽段的东支主干断裂,目前对其合肥盆地段第四纪活动特征的研究不足。通过在断裂沿线关键隐伏地段开展浅层地球物理勘探(高密度电法与地质雷达探测),以及在基岩出露区开展遥感解译与露头剖面调查工作,对该断裂合肥盆地段的几何展布特征与第四纪活动性进行初步探讨。结果表明:(1)嘉山—庐江断裂平面上主要从浮槎山以东的古河盆地内部经张八岭隆起内部向北延伸,与浮槎山东麓、张八岭隆起西麓展布的藕塘—清水涧断裂在名称上不宜混用;(2)嘉山—庐江断裂合肥盆地段局部存在较好的线性影像特征,断裂控制线性沟谷、山脊及部分河流的展布,表明其具有新活动性;(3)嘉山—庐江断裂合肥盆地段最新活动为逆冲性质,最新活动时代为中更新世中晚期。

Abstract:

The Jiashan—Lujiang fault is a major fault of the eastern branch of the Anhui section of the Tan—Lu fault zone, yet the Quaternary activity characteristics of the Hefei Basin section remain understudied. This paper presents an initial investigation into the geometric distribution characteristics and Quaternary activity of the Hefei Basin section. The study used shallow seismic exploration (high-density electrical exploration and ground-penetrating radar detection) in key concealed areas along the fault, as well as remote sensing interpretation and outcrop profiling in the bedrock outcrop areas. The results indicate that: (1) The Jiashan—Lujiang fault mainly extends northward from the interior of Guhe Basin, located east of Fucha Mountain, through the Zhangbaling Uplift. It should not be confused with the Outang—Qingshuijian fault, which is situated at the eastern foot of Fucha Mountain and the western foot of Zhangbaling Uplift; (2) The Hefei Basin section of the Jiashan—Lujiang fault exhibits distinct linear features, influencing the distribution of linear valleys, ridges, and some rivers, indicating recent activity; (3) The latest activity of the Hefei Basin section of the Jiashan—Lujiang fault is characterized by thrusting, with the most recent movement occurring during the middle-late period of Mid-Pleistocene.