首页|珠江口盆地西江凹陷裂陷期构造转换及其对沉积的意义

珠江口盆地西江凹陷裂陷期构造转换及其对沉积的意义

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珠江口盆地珠Ⅰ坳陷在早始新世—早渐新世的裂陷期主要经历了珠琼运动Ⅰ幕和Ⅱ幕,发育文昌组和恩平组.西江凹陷位于珠Ⅰ坳陷西部,凹陷内番禺4洼是已证实的富生烃洼陷,西江主洼和西江36洼勘探程度较低.为了进一步认识西江凹陷在裂陷期的构造特征及其对沉积的控制,本文利用最新三维地震数据和解释成果,结合有限的钻井资料,对文昌期和恩平期的洼陷结构、断裂体系、沉降中心迁移规律及沉积体系分布等进行了系统分析.研究发现:西江凹陷在裂陷期发生了构造转换,主要体现在早文昌期、晚文昌期和恩平期的洼陷结构、断裂体系和控洼断层活动性的规律性变化以及沉降中心的迁移;沉积中心与沉降中心迁移基本一致,早、晚文昌期各洼陷发育半深湖—深湖亚相,沉积中心向西南迁移,恩平期沉积中心转向北部西江主洼一侧;裂陷期区域伸展应力方向的顺时针旋转,以及北西向先存断裂在文昌期的先后活化是构造转换的诱因,其控制了沉积体系的展布.分析西江凹陷的构造转换和沉积体系展布规律,对在珠Ⅰ坳陷深部寻找湖相烃源岩和富生烃洼陷具有一定意义.
Tectonic Transformation of Xijiang Sag During Rifting and Its Significance to Sedimentation in Pearl River Mouth Basin
During the Early Eocene-Early Oligocene rifting period,the Zhuyi depression in the Pearl River Mouth basin mainly experienced acts Ⅰ and Ⅱ of the Zhu-Qiong movement and developed the Wenchang and Enping Formations.Xijiang sag is located in the west of Zhuyi depression.Panyu 4 sag is a proven hydrocarbon-rich depression,while Xijiang main sag and Xijiang 36 sag are not well explored.Based on the latest 3D seismic data and interpretation results,combined with limited drilling data,this paper systematically analyzes the sag structure,fault activity,migration of subsidence center and distribution of depositional system during the Wenchang period and Enping period.It is found that the tectonic transformation during the rift period is mainly reflected in the regular changes of sag structure,fault system,and the migration of subsidence center during the Early Wenchang,Late Wenchang and Enping periods.The migration of the depositional center is consistent with the subsidence center.The subfacies of semi-deep lake and deep lake were developed in the Early and Late Wenchang period,and the depositional center moved southwestern.The depositional center shifted to the north side of Xijiang sag in Enping period.Under the background of clockwise rotation of regional extensional stress direction,the activation of NW trending pre-existing faults in Wenchang led to the transformation of sag structure,fault activity and subsidence center,which controlled the distribution of the depositional system.The tectonic transformation and depositional system distribution of Xijiang depression have a certain significance for searching lacustrine source rocks and hydrocarbon-rich sag in the deep part of Zhuyi depression.

Pearl River Mouth basinXijiang sagZhu-Qiong movementregional stresstectonic transformationdepositional system

李康、单玄龙、郝国丽、热西提·亚力坤、徐川、沈梦蓉

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吉林大学地球科学学院,长春 130061

珠江口盆地 西江凹陷 珠琼运动 区域应力 构造转换 沉积体系

中海石油重大科技专项国家自然科学基金项目国家自然科学基金项目

CNOOC-KJ135ZDXM37SZ4179045341972313

2024

吉林大学学报(地球科学版)
吉林大学

吉林大学学报(地球科学版)

CSTPCD北大核心
影响因子:1.062
ISSN:1671-5888
年,卷(期):2024.54(4)