辽东湾坳陷新生代构造特征及演化

CENOZOIC TECTONIC CHARACTERISTICS AND EVOLUTION OF LIAODONG BAY DEPRESSION

辽东湾坳陷位于渤海海域东北部,是新生代渤海湾盆地内部重要的油气富集区,其构造特征复杂,体现了多期构造演化、多动力源背景的叠加效应。运用地震三维连片资料、磷灰石裂变径迹反演法和平衡剖面分析技术对辽东湾坳陷构造发育及演化特征进行了分析,研究表明:辽东湾坳陷发育7条主控断裂,整体呈NNE走向,控制了凸起和凹陷的形成;郯庐断裂带在辽东湾段发育有3条分支断裂,分别为辽西走滑断裂带、辽中1号断裂、辽东1号断裂;坳陷内发育"三凸四凹"7个次级构造单元,西部凸起连续性好,形成时间早,隆升强度大;东部辽东凸起不连续,南段形成时间早,隆升强度大,北段形成时间晚。

The Liaodong Bay Depression,located in the northeast of the Bohai sea,is an important oil and gas zone within the Cenozoic Bohai Bay Basin.The Bohai Bay is a basin characterized by complex structures,resulted from superimposition of multiple stages of tectonic evolution and dynamic processes.Based on 3-D seismic data,apatite fission track,and balanced cross-section analysis,structural development and tectonic evolution of fracture systems,tectonic styles and basin structures are studied in this paper.It is revealed that the NNE-trending fault system,which includes seven 1 st order faults in the Liaodong Bay Depression,controls the formation of uplifts and sags on large scale.The Tanlu fault zone has three branches extending into the Liaodong Bay Depression i.e.the Liaoxi strike slip fault zone,the Liaozhong 1 fault and the Liaodong 1 fault.There are three uplifts and four sags developed in the Liaodong Bay Depression.The western uplift is continuously extended.It formed in early stage and was strongly uplifted while the eastern uplift is not continuous.Its southern part uplifted earlier and strong,while the northern part formed later and has obvious differences.