黄骅坳陷南、北构造差异演化研究

Differential Evolution of South and North Structure in Huanghua Depression

为了揭示黄骅坳陷南、北区中、新生代不同的构造运动机制,明确南、北区盆地构造差异。本文以黄骅坳陷南区沧东凹陷和北区岐口凹陷为研究对象,利用地震资料开展构造分析,研究沧东凹陷和岐口凹陷构造样式、古构造格局和演化过程,探讨南北构造差异性形成机制。研究结果表明:沧东凹陷中、新生代经历了小幅度的沉降-抬升,经过2次构造转换形成断坳型盆地;受到沧县隆起、埕宁隆起和孔店凸起的三向围限,沧东凹陷整体呈现出两堑夹一垒构造格局,表现为滚动背斜构造;岐口凹陷中、新生代在同沉积铲式正断层控制作用下,经过大幅度沉降-抬升、3次构造转换形成断陷型盆地;岐口凹陷向具有较大伸展空间的海域方向延伸,而表现为半地堑或地堑式开阔盆地。

In order to reveal the different structure movement mechanism of Mesozoic and Cenozoic in the north and south areas of Huanghua depression, the differences of basin evolution in the north and south areas are discussed. Taking Cangdong Sag and Qikou Sag in the south and north of Huanghua Depression as the research object, this paper used three-dimensional seismic data to carry out structural analysis to analyze the present structural style, palaeotectonic framework and evolution process of Cangdong Sag and Qikou Sag, and discusses the formation mechanism of the difference between north and south structures. The results show that Cangdong sag experienced a small range of subsidence and uplift in Mesozoic and Cenozoic, and formed a fault-depression basin through two structural system changes. Due to the three-way confinement of Cangxian uplift, Chengning uplift and Kongdian uplift, the whole basin presents a two-grab-sandwich-one-barrier structure style, which is a rolling anticline structure.Under the control of synsedimentary plade-type normal faults in Mesozoic and Cenozoic, Qikou Sag formed a faulted basin through substantial subsidence, uplift and three structural system changes. Due to the free extension of the connection with Bozhong Depression in the sea direction, Qikou Sag appeared as a half-graben or graben-type open basin.