霸县凹陷文安斜坡断裂特征研究

Research on Wen'an slope fracture features of Baxian sag

通过对文安斜坡分析发现,研究区断裂发育主要为同生正断裂、后生正断裂以及走滑断裂,其中以同生正断裂为主。根据断裂的组合特征将研究区分为五个断裂带:长丰镇-文安垒堑式断裂带、赵各庄-左各庄垒堑式断裂带、史各庄-苏桥垒堑式断裂带、台山走滑断裂带、信安镇垒堑式断裂带。从晚中生代至今,断裂发育呈弱-强-弱的变化规律,孔店组-沙二段沉积期,断裂发育最为强烈,其次为沙一段-东营组沉积期,新近纪、中生代晚期和第四纪断裂活动最弱;晚中生代至古近纪发育的断裂为斜坡带主干断裂,对文安斜坡古近系构造发育起到了控制作用,新近纪至今发育的后生断裂对前期构造起到了复杂化的作用。研究区平面上沿构造走向从南西至北东断裂发育呈较强-强-弱-强-较强的变化规律,垒堑式断裂带中地垒与地堑的交汇处和台山走滑断裂带的断裂活动最强。

According to the Wen'an slope analysis ofBaxian sag, the main faults are syngenetic normal faults, epigenetic normal faults and strike-slip faults, in which mainly are syngentic faults. According to the combination of fracture characteristics, the study area was divided into fivefaults: Changfeng Town-Wen'an graben and horst faults,Zhaogezhuang-Zuogezhuang graben and horst faults,Shigezhuang-Suqiao graben and horst faultsw, Taishanstrike-slip fault zone, Xinan Town graben and horst faults.Dated from the late Mesozoic, fault development followed byweak-strong-weak variation rule, in Kongdian forma- tion-Sha Ⅱ deposition period, developed with the strongest faults, then in Sha Ⅰ-Dongying deposition. The Neogene, late Mesozoic and the Quaternary developed with the weakest fault activity; Late Mesozoic to Paleogene developed slopemain faults, which has played a controlling role in Wen'anslope Paleogene tectonic evolution, the epigenetic faults developed from neogene has played a complicated role to pretectonic. Variation rule shows strong-strong-weak-weakin the study area along the structure toward the plane fromthe Southwest to the Northeast. In the graben and horstfaults, faulting activity is the strongest in the intersection ofthe graben and the horst, and Tanshan strike-slip faultingzone.