渤海海域辽北潜山中新生代差异演变与形成机制

Meso-cenozoic differential evolution and formation mechanism of buried hills in Liaobei area,Bohai sea

渤海海域辽北地区潜山构造广泛发育,但其构造演变过程尚缺乏系统研究。基于钻井资料和三维地震资料的精细解释,本文识别总结了辽北地区潜山的结构特征和构造样式类型,首次厘定了潜山内幕断裂发育的期次、类型和活动特征,并结合前人研究结果,系统恢复了关键构造期古构造格局和潜山发育演变过程。研究表明:①渤海海域辽北潜山整体缺失古生界,潜山结构类型分为一元型和二元型两种,内幕识别出挤压、反转、伸展、走滑4类不同性质构造样式。②该区整体经历了太古代、元古代陆块克拉通化完成—加里东期、海西期垂向隆升—印支期挤压造山—燕山期反转改造—喜山期断陷定型。多期次、多方向、多性质构造演化叠合控制了辽北潜山带的构造格局、潜山内幕断裂发育和地层差异展布。潜山内幕主要发育北西向和北东向2组断裂,形成了复杂网格状断裂系统。

Buried hill structures are widely developed in Liaobei area of Bohai sea,but there is a lack of systematic study on their evolution.Based on accurate interpretation of drilling data and 3D seismic data,this paper identifies and summarizes the structural characteristics and structural style types of buried hills in Liaobei area of Bohai sea,determines the development stage,type and activity characteristics of interior faults of buried hills for the first time,and systematically restores the paleotectonic framework and the development and evolution processes of buried hills in key tectonic stages in combination with previous research results.The results show that①There is no Paleozoic in the whole buried hills of Liaobei area,Bohai sea,and the structural types of buried hills can be divided into two types unitary type and binary type.Four types of structural styles with different properties,such as compression,inversion,extension and strike-slip,are identified inside the buried hills.②The whole area underwent the completion of cratonization of Archean and Proterozoic continental blocks,vertical uplift in Caledonian and Hercynian periods,compressional orogeny in Indosinian period,inverse transform in Yanshanian period and fault depression in Himalayan period.Multi-stage,multi-direction and multi-attribute tectonic evolution superimposition controls the tectonic framework,interior fault development and stratigraphic differential distribution of buried hill belt in Liaobei.There are mainly two groups of faults in NW and NE directions inside the buried hills,forming a complex grid fault system.