渤海南部地区潜山构造差异与成因机制

Tectonic Difference and Genetic Mechanism of Buried Hill in Southern Bohai Area

目前,针对渤海南部潜山地层结构、构造演化的研究较少.应用三维地震资料、钻井资料,系统分析了该区潜山断裂类型、地层构造类型、成因演化和动力学背景.研究表明,近南北向郯庐走滑断裂和近东西向反转断裂共同控制了研究区潜山地层分布,进而造成了研究区潜山地层的结构、构造差异.近南北向郯庐走滑断裂为调节东西两侧挤压强度差异的同印支造山期断层.郯庐走滑断裂西支以西挤压变形强度相对较弱,普遍发育古生界薄底或秃底构造,以"中生界+古生界+前寒武系"三层结构为主;以东挤压变形作用则相对较强,表现为强烈隆升,古生界剥蚀殆尽,为"中生界+前寒武系"双层结构,花状走滑构造发育.近东西向反转断层为印支期逆冲断层,燕山期伸展反转,现今断裂上升盘残存古生界,下降盘古生界剥蚀殆尽.横向挤压收缩差异是导致研究区潜山地层结构、构造差异的主要原因.

At present,there barely have studies on the stratigraphic structure and tectonic evolution of the buried hill in southern Bohai Sea area. Combined with the 3 D seismic data and well data,this study was carried out on the fault types of the buried hills,the structural styles of the buried hills and the genesis and evolution of the buried hills and dynamic background of the buried hills. The results show that the Tanlu strike-slip faults trending near SN direction and the extension faults trending near EW direction jointly controlled the stratigraphic distribution of the buried hill strata,thus affecting the structural differences of the buried hill strata. The Tanlu strikeslip fault trending near SN direction was transform fault in Indo-Chinese epoch,which regulated the compressive strength of the both sides of east and west. The compressive deformation is relatively weak on the west side of the west branch of the Tanlu strike-slip fault,which led to the general development of ＂ thin based＂ or ＂ bald based＂. Paleozoic structures that are dominatated by three-layer-structures of Mesozoic＋Paleozoic＋Precambrian. The compressive deformation on the east side of the west branch was relatively strong,which led to the development of strong uplift,where the Paleozoic stratum has been completely eroded and two-layer-structures of Mesozoic＋Precambrian dominate. The reverse faults trending near EW direction were thrust faults in Indo-Chinese epoch,and developed extension and inversion in late Yanshan epoch,in which Paleozoic still remains in upthrow side of the fault but almost completely eroded in downthrow side of the fault. The diversity of the amount of lateral extrusion shrinkage was the main cause for the difference of structural styles of the buried hills in the study area.