Abstract: The Toupo Fault,located in the southern Anhui Province,strikes N60°～70°E in a linear route that is clear on satellite image. It plays an important role in controlling the tectonics,topography and distribution of Mesozoic-Cenozoic basins and strata. Detailed field investigation was carried out along the Toupo Fault about its activity. Profiles as well as a trench excavated reveal that the Quaternary superstratum above the fault has not been offset. The stratum was sampled and dated with TL methods to be the Mid-Pleistocene time,implying that the fault has been no longer active since then. Three stages can be divided since the fault was formed,namely,the first stage (late Yanshan Movement),when the fault movement was of reversal left-lateral strike-slipping and the tracks formed then are still clear today; the second stage (early Himalayan Movement-the late Cretaceous-early Tertiary),when the fault movement turned to be normal faulting and the southern wall became a tensile basin and received clastic sediments; and the third stage (since the late Tertiary),when the tectonic movement was very week. No late Tertiary sediments were formed and the Quaternary sediment is only as thick as tens meters. The topography also suggests an old-age form. Neither vertical nor horizontal displacement was evident along Toupo Fault during this stage,though fault gouge dating suggests the Toupo Fault might have been active during the Middle Pleistocene.

Key words: Quaternary, fault activity, Anhui, the Toupo Fault

摘要： 对位于安徽南部的头坡断裂的野外调查表明,沿头坡断裂没有明显的水平或垂向错动的地貌现象;在取得的剖面中,上覆第四纪地层均未被断裂断错,表明断裂在中、晚更新世以来没有活动。对本区地貌、第四纪地层和断裂活动历史的调查分析表明,该断裂在燕山运动晚期(侏罗纪末—早白垩世)和喜马拉雅运动早期(晚白垩世—古近纪)有过2次强烈活动,前者表现为左旋走滑运动,后者以拉张活动为特征。新近纪以来全区处于长期隆升剥蚀状态,缺失新近系,第四系厚度不大,残坡积地层广泛发育,构造运动微弱。头坡断裂的活动历史及新活动性与其相邻的郯庐断裂带南段相似,前者可能受后者的控制。

关键词: 第四纪, 断裂活动性, 安徽, 头坡断裂