海相油气地质2025，Vol.30Issue(3)：217-227,11.DOI:10.3969/j.issn.1672-9854.2025.03.003
东非鲁伍马盆地上始新统海底扇发育演化特征
Development and evolution of the Upper Eocene submarine fan in Rovuma Basin,East Africa
摘要
Abstract
The interaction between deep-water gravity flow and bottom flow is a currently hot topic in deep-water sedimentary research in the world.This study focuses on the Upper Eocene of the Rovuma Basin in East Africa,utilizing a comprehensive approach integrating drilling and 3D seismic data to investigate this geological topic.The sedimentary architectural elements and evolution characteristics under a high-frequency sequence stratigraphic framework is studied to reconstruct the depositional and evolutionary patterns of the submarine fan under the interaction of gravity and bottom currents in the Upper Eocene.The results show that:(1)The Upper Eocene submarine fan in the study area develops three types of sedimentary architectural elements:deep-water channels,overbanks and lobes.The channels can be further divided into two types:confined deep-water channels and semi-confined unidirectionally migrating channels.(2)The Upper Eocene third-order sequence can be divided into three fourth-order sequences:Ps1,Ps2 and Ps3.Among them,the Ps1 sequence develops a confined deep-water channel-lobe complex,the Ps2 sequence develops a semi-confined unidirectionally migrating channel-lobe complex,and the Ps3 sequence develops a lobe complex.The evolution of these sequences represents a cyclic evolution process within the third-order sequence under the background of continuous rise in sea level,changes in seafloor landform filling,attenuation of gravity flow energy,and relative enhancement of bottom currents.(3)Bottom currents could strip fine-grained materials in gravity flows accumulate on the northern side(downstream side of the bottom current)of the deepwater depositional system,forming asymmetric overbank/drift deposits with positive topography.This,thereby,restricts channels and lobes to southward erosion and deposition,resulting in the Eocene deepwater depositional system and depositional architectural elements that exhibit a unidirectional migration and stacking pattern on the upcurrent side.It is inferred that bottom currents may enhance the reservoir quality of gravity flow deposits.关键词
重力流/底流/交互作用/沉积结构单元/单向迁移/深水沉积/海底扇/鲁伍马盆地Key words
gravity flow/bottom current/interaction/sedimentary architectural elements/unidirectionally migrating channels/deep-water sediments/submarine fan/Rovuma Basin分类
石油、天然气工程引用本文复制引用
吴佳男,李祥权,丁梁波,张颖,解习农,左国平,彭志浩..东非鲁伍马盆地上始新统海底扇发育演化特征[J].海相油气地质,2025,30(3):217-227,11.基金项目
本文受海洋地质资源湖北省重点实验室开放基金(编号:MGR202303)资助 （编号:MGR202303）
