郯庐断裂带在渤海海域渤东地区的构造特征

为了分析郯庐断裂带对渤海海域渤东地区的构造特征、构造演化及油气成藏的控制作用,解释了5条地震剖面,并对其中一条剖面做了平衡恢复。研究结果表明,郯庐断裂在渤东地区表现为3个分支,剖面上发育明显的负花状构造、具有走滑性质的正断层、滚动背斜、垒堑构造、断阶构造等,还可见海豚效应现象。平面上深部走滑断层延伸较远,浅层形成大量的雁列式正断层。郯庐断裂古近纪主要以伸展活动为主,且以渐新世东营组沉积期伸展活动最强,上新世-第四纪以走滑活动为主。因此,渤东地区断裂具有分层差异变形特征,基本上可以分为两套断层系统:1古近系及其下部的伸展断层系统;2新近系-第四系的走滑断层系统。郯庐断裂的晚期强烈活动促使了油气的晚期成藏。

Tectonic characteristics of the Tanlu fault zone in Bodong area of Bohai Sea

The Tanlu fault zone control the tectonic characteristic, tectonic evolution and hydrocarbon accumulation in Bodong area. The explanation results of five seismic sections show that the Tanlu fault has three branches in this area.There developed the negative flower structures and the normal faults with strike-slipping displacement, rollover anticline, horst and graben, redan, as well as the dolphin effect phenomena on the tectonic sections. The strike-slip fault extended a long distance in the deep part,while lots of en-echelon normal faults were developed in the shallow part. The balanced section analysis of the Tanlu fault zone showed that the extension was the main activity in the Paleogene Period and the most intense extension was in the sedimentary period of Oligocene Dongying Formation,while the strike-slipped activity existed mainly from the Pliocene to the Quaternary. The faults in the Bodong area had evident characteristics of differential delaminating deformation and could be divided into two sets of fault systems, including the normal fault system in the Paleogene System and pre-Paleogene System, and the strike-slip fault system in the Neogene and the Quaternary. The late intense tectonic movement of the Tanlu fault zone enhanced the late-period hydrocarbon accumulation in the Bodong area.