浅述深水水道的形态学特征

Brief introduction to morphological characteristics of deep-water channels

目前深水水道的分类方案较多,本文基于深水水道的形态学特征,且聚焦于单一型深水水道,将其划分为顺直型(曲率介于1~1.25)、低弯度S型(曲率介于1.25~1.5)和高弯度S型(曲率>1.5)。其中,顺直型水道侵蚀作用最强,往往不发育天然堤沉积,无侧向加积;低弯度S型水道发育天然堤,并具有侧向加积;高弯度S型天然堤及侧向加积最为发育,决口扇常与之伴生。深水水道的曲率是水道形态的直观表现,曲率大小主要受深水地貌即深水地形坡度的影响。在上陆坡区域,地形坡度较大,沉积物能量强,深水水道以顺直型为主。中陆坡区域,随着地形坡度的减缓,水道的弯曲形态也逐渐增加,形成低弯度S型,直至下陆坡,水道演变为高弯度的S型。

At present,there are many classification schemes for deep water channels.This paper is based on morphological characteristics of deep water channels and focuses on a single type of deep water channel which is furtherly divided into straight-type(curvature between 1-1.25),low-s-type(curvature between 1.25-1.5)and high-s-type(curvature>1.5).The straight-type channel has the strongest erosion characteristics without natural levee deposition and lateral accretion.Low-s-type channel is develped with the levee deposition and lateral accretion.And high-s-type channe lis mostly developed with levees and lateral accretion and often ccompanied by crevasse fan.The curvature of the channel is the direct manifestation of the shape of channel is mainly affected by the deep-water topographic feature.In the upper continental slope area,the slope is steep with strong sediment energy the channel is mainly straigh type,in the middle area,the slope become gentle,the low-s-type dominant,in the lower slope,and the channel evolves into a high-curvature s-type.