长江河口及其水下三角洲的沉积特征和沉积环境

近两千年来,长江河口河道束狭淤浅,南岸边滩伸展,河槽成形,河道加深,形成现代河口的形态。长江河口的沉积物分布是和河口地形及水下三角洲的发育密切相关的。本文研究了沉积特征以及它与沉积环境、地貌和水文特征之间的关系。大量材料分析表明,沉积物的粒度大小和水动力条件相适应,分选系数、偏态和中值粒径之间有相关性。长江河口可分为四个沉积区:河口段上段沉积区;河口分汊河段沉积区;河口拦门沙沉积区;水下三角洲沉积区。

Sedimentary Characteristics and Environment of the Changjiang Estuary and its Submerged Delta

The Changjiang estuary has undergone narrowing and shallowing of the channel, the growth of shoals at the south bank, formation of the regular river channel, deepening of the channel, The modern estuarine conguration is formed the last 2000 years. The estuarine sediment distribution is closely related to the estuarine topography and submerged delta. The author triss to study the relationship between the sedimentary characteristics and its environment as well as geomorphological and hydroligical conditions. The grain size of sediment corresponds to its dynamic conditions according to analyse a large amount of data, The correlativity between the sorting coefficient, skewness and median size is prosented. There are four sedimentary areas in the Changjiang estuary. The upper reach sedimentary area of the estuarine reach. Tne Sedmentary area of the bifurcated reach, The sedimentary area of the mouth-bar. The submer ged delta's sedimentary area.