郯庐断裂带辽东湾段新生代右旋走滑变形及其模拟实验

郯庐断裂带是一条区域性深断裂带,地球物理勘探资料表明郯庐深断裂主位移带在辽东湾坳陷大致沿坳陷东部边缘通过.辽东湾坳陷东部沿辽东凸起两侧发育有若干陡倾或近直立的断层.这些断层自盆地基底一直切割到新近系中,部分断层甚至切割到更新统及全新统.在辽东凸起南段,断层表现为向南西撒开、向北收敛的帚状断层组合,所有断层在剖面上均显示正断层位移特征;在辽东凸起北段,断层表现为向北北西发散、向南收敛的羽状断层组合,西侧的部分断层在剖面上具有明显的逆冲断层位移特征.辽东凸起附近盆地盖层中的断层组合表明,北北东向断层在新生代有明显的右旋走滑运动.沙箱模拟实验表明,沿辽东凸起南、北两段的断层组合可能与郯庐深断裂新生代右旋走滑位移有关,断层组合形式、运动性质的差异可能与郯庐深断裂主位移带走向变化有关.

Characteristics and modeling of the Cenozoic right-lateral slip deformation in the Liaodong Bay segment of the Tan-Lu fault zone

The Tan-Lu fault belt is a regional deep fault belt.Geophysical data show that the main shift zone of the Tan-Lu fault goes roughly along the eastern margin of the Liaodong Bay depression.Several steep and near-vertical faults were developed along both sides of the Liaodong uplift in the eastern part of the Liaodong Bay depression.These faults cut all strata from the basement to the Neogene,and some of them even cut the Pleistocene and Holocene.In the southern part of the Liaodong uplift,the faults occur as a broom-like fault complex diverging to the south-west and converging to the north.In section,all the faults show features of normal fault displacement.In contrast,in the northern part of the Liaodong uplift,the faults occur as a feather fault complex diverging to the north-northwest and converging to the south.In section,some faults in the west show distinct characteristics of thrust fault displacement.Fault complex in the sedimentary cover of the basin near the Liaodong uplift reveals that,during the Cenozoic,the north-northeast-trending faults experienced obviously right-lateral slip activities.Sandbox simulation experiment indicates that the fault complexes along the northern and southern parts of the Liaodong uplift may be related to the Cenozoic right-lateral slip movement of the Tan-Lu fault.The differences in fault complex and movement may be related to changes of strikes of the main shift zone of the Tan-Lu fault.