郯庐断裂带庐江段嘉山-庐江断裂第四纪活动特征

Quaternary Active Features of Jiashan-Lujiang Fault on the Lujiang Segment of Tanlu Fault Zone

郯庐断裂带庐江段嘉山-庐江断裂位于大别山东侧的山前盆地内,断裂线性特征较明显,沿一系列NNE向长条状低丘边缘展布。本文对该断裂开展了野外调查,为了确定断裂的形迹及其活动性,我们沿长条状低丘边缘进行详细的追索,发现了多个典型的断层剖面,并采集了断层泥ESR年龄样品。3条剖面中断层特征相似,倾角都较陡,沿断面可均见近水平擦痕,显示该断裂是一条倾角较陡的以走滑为主的断裂。结合断层地貌特征、断层泥测年结果及区域内重要断裂的构造对比,认为郯庐断裂带庐江段嘉山-庐江断裂是一条中更新世断裂。断裂的第四纪活动情况与断裂所在地的弱地震活动水平有关。

The Jiashan-Lujiang fault on the Lujiang segment of the Tanlu fault zone is located in the foreland basin on the east side of Dabie Mountains,and the linear features of it are clear.The fault spreads along the edge of NNE trending long strip hills.In order to determine the trace and activity of the fault,we carried out field geological survey along the edge of the long strip hills,including profile description and ESR samples collecting.In the three fault profiles,the characteristics of the faults are similar,with steep dip angles and nearly horizontal scratches along the fault.The results show that it is a strike slip fault with steep dip angle.Combined with the characteristics of fault landform,dating results of fault gouges and the comparison of structure of important faults in the region,we believe that the Jiashan-Lujiang fault on the Lujiang segment of the Tanlu fault zone is a middle Pleistocene fault.The Quaternary activity of the fault is related to the weak seismicity in the study area.