渤海海域主要新构造活动断裂带

The neo-tectonic active fault zone in the Bohai Sea

摘要:

渤海位于渤海湾盆地的东部，是我国华北地区新构造活动最强烈的地区之一，盆地内的沉积盖层（N-Q）中断裂极为发育。许多研究者从不同角度对渤海新构造进行过研究，但认识不一。笔者基于以往的工作，对该区新构造作了较深入的分析，确定渤海新构造运动起始于中新世晚期（12~10Ma BP）。从三维空间分析盖层断裂，并按其与盆地基底断裂的成因关系，将新构造活动的断裂分为继续活动断裂和新生断裂，并划分出3条主要的新构造活动断裂带：北东（偏北）向营口-潍坊断裂带北段是继续活动构造带，右旋逆平移活动，活动性弱；北西西向北京-蓬莱断裂带亦为继续活动构造带，左旋正平移活动，活动性较强；北东向庙西北-黄河口断裂带为新生构造带，右旋平移活动，活动性强。后两者组成一对以庙西北-黄河口断裂带为主的偏共轭活动构造带，该区域地震活动与之关系密切。最后探讨了渤海地区新构造期北东东-南西西至近东西向水平挤压的构造应力场及其与新构造活动断裂带发育的关系。提出新构造应力场与古近纪盆地裂陷阶段的应力场截然不同，新构造为地壳共轭剪切破裂系统，古近纪盆地构造是发育于地壳上部的伸展构造系统，这是两期不同体制的构造系统。

Abstract:

The Bohai Sea lies in the east of the Bohai Basin. It's a place where neo-tectonic activity is strong in North China. Faults are common in the sedimentary strata of the basin. Many researchers have studied the neo-tectonics of the Bohai Sea from different aspects,and get different conceptions. The authors have made a number of studies of the neo-tectonics of the Bohai Sea and confirmed the neo-tectonics in the Bohai Sea began from the later of Neogene(12~10Ma BP). We also studied the faults distribution from three-dimensional space,and divided the neo-tectonic faults into the continued active faults and the newly formed faults on the basis of the genetic relationship of basement faults. They could be divided into three major neo-tectonic activity fault zones,the Yingkou-Weifang fault zone of north-northeast with continuous activities and weakly active right lateral thrust movement,the Beijing-Penglai fault zone of northwest-west with continuous activities and strongly active left lateral positive movement,the Northwest Miao Island-the Yellow River Estuary Fault zone of northwest which is newly formed with strongly active right lateral translational movement,. The latter two formed a partially conjugated active tectonic zone,dominated by the Northwest Miao Island-the Yellow River Estuary Fault zone,and the seismic activity has close relationship whit it. Finally,the neo-tectonic stress field of northeast-east-southwest-west horizontal conpression,and its relationship with neo-tectonic active fault zones have been discussed. The neo-tectonic stress field is quite different from the rift stage of the Bohai basin in the Paleogene. The neo-tectonics is the crust conjugate shear rupture system. The Paleogene basin tectonics is extensional structure in the upper crust,which forms two different structural systems under different tectonic mechanism.