荔湾凹陷是珠江口盆地最南部的一个超深水凹陷,其结构特点、沉积过程研究是认识被动陆缘演化的重要内容.运用地震地层学方法,基于高分辨率2D/3D地震资料的沉积追踪与对比,一个特征明显且全区可追踪的地质界面——SB21界面被识别出.该界面上下揭示出多种沉积现象:北部剥蚀区、中北部的沉积物过路区、中南部冲沟和沉积物波叠置区、南部的沉积物堆积区.推测这种沉积样式的多样性与发生在23.8Ma前后的白云运动有密切关系,该构造运动造成荔湾凹陷的差异性沉降,主要表现为荔湾凹陷中南部的快速沉降,导致凹陷北部及中东部的相对抬升.该期构造运动使原有的沉积平衡发生改变,造成沉积物的再分配,沉积物从北部剥蚀区经过路区向中南部堆积区运移.自东向西发育的冲沟,推测与该时期差异沉降导致中东部近南北走向的相对隆起与西侧沉降区的差异沉降,以及有来自凹陷东北角的物源叠加作用有关.SB21界面的沉积反射特征研究,揭示了洋陆边界复杂多变的沉积过程及其驱动机制,对我们认识更大区域的构造沉积过程具有一定的帮助. The Liwan sag is an ultra-deepwater sag in the southernmost part of the Pearl River Mouth Basin, and its structural features and sedimentary processes are important contents for understanding the evolution of passive margins. Using the method of seismic stratigraphy, sediment tracing based on high resolution 2D / 3D seismic data and In contrast, a well characterized and regionally-traceable geological interface, the SB21 interface, has been identified, revealing numerous sedimentary up and down features: northern denuded zones, central-northern sedimentary zones, central-southern gully and sediments Wave superimposed area and southern sediment accumulation area.It is speculated that the diversity of this sedimentary pattern is closely related to the Baiyun movement occurring before and after 23.8Ma and this tectonic movement caused the differential settlement of Liwan sag, mainly in the Liwan sag The rapid subsidence in the south led to the relative uplifts in the northern and middle eastern sags, and the tectonic movement altered the original sedimentary balance and resulted in the redistribution of sediments from the northern denuded zone to the central and southern accumulated zone The development of the gully from east to west, suggesting that the differential settlement during this period led to the central and eastern parts of the recent uplift of the north-south trending and the difference between the sedimentation area on the west side , As well as the superimposition of provenance from the northeastern corner of the depression.The study on sedimentary reflection characteristics of SB21 interface reveals the complex and changeable sedimentary process and its driving mechanism at the boundary of the oceanic land and has a definite effect on the tectonic sedimentation process of our understanding of the larger area s help.