【摘要】 合肥盆地早白垩世演化过程长期存在争议.利用最新的油气勘探地震资料,系统分析了盆地内主要断层及其东缘的郯庐断裂伸展活动在地震剖面上的构造表现,并在此基础上论述了合肥盆地东部白垩系朱巷组、响导铺组、张桥组的断裂—沉积响应.结合同位素年代学资料综合分析认为,合肥盆地伸展活动的起始时间为早白垩世中期,持续至古近纪末.同时采用2DMOVE模拟软件对断层的分析也支持了这一认识.该时期合肥盆地呈现复合式断陷构造格局,盆地东西部受北北东向郯庐断裂带与吴集断裂的伸展作用控制,出现了北北东向的半地堑式断陷盆地.同时,盆地北界及内部近东西向南倾断裂(寿县—定远断裂、肥中断裂、肥西—韩摆渡断裂)的伸展活动,又控制出现了近东西向、北断南超的半地堑式盆地,总体上为复合断陷盆地,其伸展活动发生在华北克拉通岩石圈减薄的背景下,与太平洋板块高角度俯冲有关.更多还原

【Abstract】 The evolution of the Hefei basin is an unresolved problem.On the basis of new seismic data across the basin and Tan-Lu fault during the Cretaceous zone,we analyzed the tectonic framework of the basin and sedimentary features of the Cretaceous Zhuxiang,Xiangdaopu,Zhangqiao Formations.The results indicate that the extension of the Hefei basin possibly started in the mid Early Cretaceous and lasted to the Paleogene.The fault analysis by 2DMOVE modeling software also supports the idea.The Hefei basin presented a complex tectonic framework in this period;the eastern and the western borders of the basin were controlled by the Tanlu normal fault and the Wuji normal fault with a NNE direction,thus forming a semi-graben with a NNE strike.At the same time,the Shouxian,Feizhong,Feixi-Hanbaidu faults were formed with NS direction within the basin to form a semi-graben which onlapped in the south and faulted in the north.So the Hefei basin was a complex faulted-depression in this period.The extension happened under the lithospheric thinning setting of the North China Craton and was related to the high angular subduction of the Pacific plate.更多还原