黄河三角洲的沉积动力分区

Sediment Dynamics in the Littoral Zone of the Yellow River Delta

以2000年及2007年黄河三角洲滨海区采集的123和155个表层沉积物样品为数据基础,经实验室分析取得各样品的粒度参数,结合地貌条件、动力条件和水深资料,探讨黄河三角洲滨海区沉积物的分布类型、粒度特征以及其动力分区等方面的规律。黄河三角洲滨海区表层沉积物类型主要为砂质粉砂;中值粒径由岸向海逐渐变细;分选系数整体偏高反映了的复杂性;偏态值均为正,其极高值大都分布于水深10m左右的区域;峰态的极大值分布于现行河口的南侧,极小值分布于湾湾沟口和飞雁滩以东的近岸。Flemming三角图反映出冲蚀区的动力条件整体较强;淤积区内清水沟老河口附近的动力条件比现行河口强;浅海平原区水动力较弱且单一。

Data from surface sediment samples collected in the littoral zone of the Yellow River Delta between 2000 and 2007 were combined with hydrodynamic and water depth information to determine the spatial distribution of sediment types,and the grain size response to the dramatic decrease in riverine sediment discharge.Sandy silt is the most widely occurring sediment grade across the study area,and grain size shows a general seaward fining trend.In the shallower region,spatial variations in surface sediment size are large,and strongly influenced by wave action through sediment re-suspension processes.Sediment samples collected in 2007 were coarser than those recovered in 2000,and this is most probably due to the erosion of the subaqueous delta following the significant decrease in riverine sediment supply.The study area was divided into three sedimentary districts based on Flemming＇s ternary diagram： the erosion area,deposition area,and neritic deposit area.