渤海湾盆地黄骅坳陷新生代沉降特征

在对渤海湾盆地黄骅坳陷区域构造特征的22条地震剖面解释的基础上,分析了黄骅坳陷沉降特征。通过对黄骅坳陷的9个主要凹陷沉降史的研究表明,黄骅坳陷新生代构造沉降量的时空差异性分布明显。时间上,黄骅坳陷具有"幕式"沉降特征,孔店组沉积期为裂陷Ⅰ幕、沙三段沉积期为裂陷Ⅱ幕、沙一段和沙二段沉积期和东营组沉积期为裂陷Ⅲ幕、馆陶组和明化镇组下段沉积期为热沉降幕、明化镇组上段和第四系的沉积期为加速热沉降幕。不同沉积期盆地沉降在空间分布上,沉降速率上都有明显差异。通过对凹陷尺度单井的埋藏史曲线,构造沉降曲线,基底沉降图和沉降中心迁移图对比分析表明,空间上,黄骅坳陷新生代沉降作用具有明显的迁移规律,总体是自南向北,自西向东迁移,现今的沉降中心位于歧口凹陷海域部分。

Tectonic subsidence characteristics ofHuanghua depression in Bohai Bay Basin in Cenozoic

The history of Huanghua depression subsidence was analyzed by explained the structural characteristics of 22 seismic profiles of Huanghua depression in Bohai Bay Basin.Based on the subsidence history of nine main sags in the Huanghua depression,it could be found that the tectonic subsidence of Huanghua depression had an obviously space-time discrepancy among the Cenozoic.The results show that the Huanghua depression underwent the episodic subsidence in the time,including the rifting episodic Ⅰ is the sedimentary period of the Kongdian Formation,the rifting episodic Ⅱ is the sedimentary period of the 3th member of the Shahejie Formation,the rifting episodic Ⅲ are the sedimentary period of the 1st and 2nd member of the Shahejie Formation and the Dongying Formation,thermal subsidence episodic are the sedimentary period of the Guangtao Formation and the lower submember of the Minghuazhen Formation,accelerated thermal subsidence episodic are the sedimentary period of the upper submember of the Minghuazhen Formation and the Quaternary.The Huahuang depression subsidence center migrated regularly in the space which was interpreted through the analysis of sags of the burial history curve,subsidence curve,subsidence features of basement and the migration of the subsidence center.The result of subsidence comparison and analysis indicates that that the subsidence center migrated from the south to the north,from the west to the east,finally,reached the largest subsidence center nowadays-the Qikou sag.