郯庐断裂带明光—定远池河镇段的新活动性

New Activity of the Mingguang-Chihe Segmented of the Tanlu Fault Zone in Anhui Province

郯庐断裂带南段淮河至女山湖段落已被证实具有晚第四纪活动性,为进一步追踪断裂带在女山湖以南的活动情况,选取明光至定远池河镇段落进行遥感解译、地质地貌调查、探槽开挖及年代样品测试等工作。研究发现,该段断裂在卫星影像上显示线性特征较差,发育断裂主要为池河-太湖断裂;断裂新活动主要表现为控制池河河谷的发育及沿明南土山村、池河石塘岳、池河周王等地展布的线性岗状地貌;在上述岗地边缘开挖探槽揭示断裂在该段最新活动方式具挤压逆冲性质,最新活动时代为中更新世,晚更新世以来不活动。上述结果初步表明,该段与其北侧相邻的淮河至女山湖段在第四纪活动性上存在差异,可能为郯庐断裂带在女山湖附近存在分段导致。

The section of Huaihe River to Nvshan Lake in the southern part of Tanlu fault zone has been beleived to be of late Quaternary activity.To trace further the activity of the fault to the south of the Nvshan Lake,we selected Mingguang south to Chihe Town section to conduct remote sensing interpretation,geological survey,trench excavation and age sample analysis.The results show that the linear features of this section are poor,and the main faults are the Chihe-Taihu fault.The new activities of the fault are mainly manifested as the control of the development of the valley of Chihe River and the hillock geomorphology along the Tushan Village in the Minguang Town,Shi Tangyue and Zhouwang Village in the Chihe Town.Excavation of trenches at the edge of the hillock revealed that the latest mode of activity of the fault in this segment is characterized by crushing and thrusting.The latest tectonic activity of the fault was the middle Pleistocene and inactivity since the late Pleistocene.The above preliminarily results show that exists the difference in Quaternary activity between this section and the Huaihe-Nvshan Lake section adjacent to the north side,possibly resulting from the subdivision of the Tanlu fault zone near the Nvshan Lake.