深水单向迁移水道-堤岸沉积体系特征及形成过程

南海珠江口盆地白云深水区及西非下刚果盆地发育一种深水单向迁移水道-堤岸沉积体系，主要包括轴部沉积、侧积体沉积、滑塌/块状搬运复合体沉积、堤岸沉积，另见阶地。该沉积体系水道整体具有单向迁移特征，为重力流和等深流共同作用而成，水道迁移方向与等深流运动方向大致相同。其影响因素包括重力流及等深流相对能量的大小、物源、海平面升降、气候、地形、科氏力及陆架宽度等。阶地成因可分为3种，即重力流侵蚀侧积体成因、沉积失衡滑塌或断层作用成因和重力流在水道内部的差异侵蚀成因。对该沉积体系的研究不仅能加深深水沉积的认识，还可为油气进一步勘探服务。

Characteristics and Processes of Deep Water Unidirectionally-migrating Channel-levee System

Unidirectionally-migrational channel-levee system well develops in the deep area of Baiyun of the Pearl River Mouth Basin,the South China Sea and in Lower Congo Basin,west Africa,which consists of thalweg deposits,laterally migrating deposits,slump deposits/mass transport complex deposits and levee deposits with terraces.The channel shows obviously migrating characteristic,which results from interaction between gravity flow and contour current.Furthermore,migrating direction of channel corresponds to the direction of contour current.It is likely to be controlled by relatively energy of gravity flow and contour current,sediment supply,fluctuated sea-level,climate,morphology,Coriolis force,width of shelf and so on.There are three geneses of terraces:(1) gravity flow incised the laterally migrating deposits;(2) sediment unbalance or fault lead to slump or slide;and(3) various incision of gravity flow in channel.Work on unidirectionally-migrating channel-levee system not only is helpful to improve knowledge of deep water deposits,but also provides a new prospect for oil and gas exploration.