济阳坳陷中、新生代构造沉降与板块聚敛速率关系探讨

Relationship between Meso-Cenozoic Tectonic Subsidence of the Jiyang Depression and Plate Convergence Rate

根据回剥模型,将钻井资料与区域地震剖面相结合,对济阳坳陷内东营、沾化和惠民3个次一级凹陷进行沉降史模拟。6口钻井的沉降曲线表明济阳坳陷中、新生代的构造沉降分为6个阶段:(1)中生代残余盆地发展阶段;(2)孔店期初始裂谷阶段;(3)沙四—沙三期断陷一期;(4)沙二—沙一期断陷二期;(5)东营期断陷三期;(6)新近纪热沉降阶段。将以上构造沉降速率同太平洋板块相对欧亚板块的聚敛速率进行比较,两者相吻合,表明太平洋板块的俯冲作用是济阳坳陷从“初始裂谷—快速沉降—裂谷逐渐萎缩—热沉降”构造演化过程的主要控制因素。

We modelled the subsidence history of three sags （the Dongying, Zhanhua, and Huimin sags） in the Jiyang depression of Bohai Basin by using well data and seismic profiles. The subsidence curves of six wells demonstrate that the Meso-Cenozoic geological history of the Jiyang depression can be divided into six phases ： （ 1 ） Mesozoic characterized by low subsidence rate; （2） Kongdian Formation when the rift originated; （3） the fourth and third members of Shahejie Formation with the rapidest subsidence; （4） the second and first members of Shahejie Formation when the fault-depression continued; （5） Dongying Formation, the terminal fault-depressed phase; （6） Neogene which is occupied by post-rift thermal subsidence. The comparison between the tectonic subsidence rate and the convergence rate of Pacific plate relative to Eurasia indicates that the Meso-Cenozoic tectonic evolution of the Jiyang depression is mainly controlled by the plate convergence.