南堡凹陷高柳地区沙三段沉积相特征及其对构造演化的响应

Sedimentary Characteristic and Its Response to the Tectonic Evolution of Third Member of Shahejie Formation in Gaoliu Area,Nanpu Sag

基于地震资料分析,并总结前人的研究,将南堡凹陷高柳地区构造演化划分为初始裂陷期、快速裂陷期、裂陷萎缩期和坳陷期;沙三段处于快速裂陷期,且沙三一沉积期发生了构造反转。综合岩芯、录井及测井资料,明确了研究区的物源方向、沉积相类型与分布规律及沉积模式。研究表明:边界断层控制下的沉积地貌背景造就了高柳地区沙三段近物源、快速堆积的扇三角洲-湖泊沉积相类型及其频繁交替的沉积序列特征。比较构造反转前后沉积模式认为:构造反转前,边界断层活动相对较弱,地貌较缓,西南庄断层控制了物源与沉积中心;构造反转后,地貌变陡,造就了扇三角洲小平原大前缘特征,柏各庄断层控制了物源与沉积中心,且西向物源变强。

Based on the seismic data and previous research,this study divide the tectonic evolution of Gaoliu area into four stages,initially rifting stage,rapidly rifting stage,shrinking stage and depression stage. The third member of Shahejie formation belongs to the rapidly rifting stage and the tectonic inversion happed at this time.Combined with the cores and logging data,this study figured out the source direction,sedimentary facies types and sedimentary model. The results show that,under the controlment of boundary fault,the sedimentary geomorphology caused the fast depositional fan-delta and lacustrine facies in the third member of Shahejie formation of Gaoliu area.Compared the before-after sedimentary model,this study unveiled that the tectonic activities is relatively weak before the tectonic inversion. The Xinanzhuang fault controlled the sedimentary source and depocenter. After the tectonic inversion,the geomorphology became steep,which caused the characteristic of big fan-delta front and small fan-delta plain. The Bogezhuang fault controlled the source and depocenter. And the west sedimentary source became strong.