现代废黄河口表层沉积物的年代际空间分布与主控因素

INTER-DECADAL VARIATIONS IN SURFACE SEDIMENT DISTRIBUTION PATTERNS OFF THE RECENTLY ABANDONED HUANGHE RIVER MOUTH AND THEIR KEY CONTROLLING FACTORS

基于现代废黄河口的不同年代表层沉积物粒度资料,研究了废河口区表层沉积物的年代际空间分布特征及变化趋势;结合水动力、地形地貌资料,探讨了影响表层沉积物空间格局的主控因素。研究结果表明,现代废黄河口表层沉积物空间分布存在限制的年代际变化特征,不同年代空间分布总体表现出近岸较粗、离岸变细的趋势。1992年研究区表层沉积物粒度总体较细;1992—2000年研究区表层沉积物显著粗化;2000—2007年大部分区域表层沉积物进一步粗化;2007—2015年研究区表层沉积物空间分布无明显变化。研究区表层沉积物的年代际空间分布特征受沉积动力环境及其导致的年代际冲—淤演变格局影响,随着研究区的抗侵蚀能力增强,其表层沉积物的空间分布基本无较大变化。

Inter-decadal variations in surface sediment distribution patterns off the recently abandoned Huanghe river mouth were studied based on the grain-size data of the surface sediment.Combined with the data of bathymetry and hydrodynamics off the abandoned river mouth,the key factors that control the temporal variations were discussed.The results indicate that the surface sediment off the recently abandoned Huanghe river mouth display a seaward fining trend at an inter-decadal scale.The mean grain size（Mz,inΦunit）of surface sediment reached its highest level in 1992.It was coarsening up from 1992 to 2000.During the period of 2000—2007,the sediment off the recently abandoned river mouth became coarser,while the surface sediments remained unchanged during the period of 2007—2015 in the study area.The variation of surface sediment is both controlled by hydrodynamics and erosion-deposition patterns of the study area.The spatial distribution of surface sediment almost kept stable with the increase in erosion resistance off the recently abandoned river mouth.