作　　者： ; ; ; ; ;

机构地区： 华东师范大学河口海岸科学研究院河口海岸学国家重点实验室

出　　处： 《地理学报》 2009年第5期629-637,共9页

摘　　要： 基于2005年7月及2007年5月在长江口拦门沙河段崇明东滩、横沙东滩(浅滩)、九段沙以及南汇边滩等四大潮滩的水下滩地采集的大面积、高密度表层沉积物以及实测水文资料,对拦门沙河段潮滩表层沉积物颗粒度、参数、组成、类型以及分布特征进行分析,并在此基础上探讨影响沉积物分布的主要动力因子。结果表明:长江河口四大潮滩表层沉积物主要由砂、粉砂质砂和粘土质粉砂三种类型组成,沉积物中值粒径分布比较复杂,介于2.5～8φ之间;沉积物分选系数集中于1～2左右,其分布与中值粒径具有一致性,其中物质组成相对较粗的颗粒分选性较好而较细的颗粒分选性较差;偏态与峰态跨度较大,分别介于0.1～0.8与1～4不等。崇明东滩、横沙东滩(浅滩)和九段沙的沉积物分选系数、偏态和峰态的分布具有一致性,三者相关性较强;南汇边滩的沉积物分选性、偏态及峰态值则因南滩与东滩所处位置差异而有较大差别。此外,河口潮滩表层沉积物分布显示泥沙输移的结果,其主要水动力因子包括潮流和波浪控制的泥沙输移;在受落潮优势流作用的地区普遍粗于涨潮优势流作用的地区;在波浪动力强、波能释放的地区沉积物普遍较粗且分选性较好;深水航道工程的堵汊、导流、破水波作用明显,使得导堤两侧的表层沉积物粒度出现粗细分布不均的特点。 Large-scale and dense sediment samples and associated hydrological data were collected in July 2005 and May 2007 from submarine sectors of Chongming Eastern Shoal, Hengsha Eastern Shoal, Jiuduan Shoal and Nanhui Shoal, which are four important tidal flats located at the mouth-bar fiver segment of the Yangtze Estuary. Based on the above data, the grain size and related parameters, compositions, classifications in sediments and their distributed characteristics are analyzed, and then mainly impacted dynamic factors on the distributions of sediments are discussed. The results are shown as follows： sediments located at these tidal flats of the Yangtze Estuary are mainly composed of sand, silty sand and silt. The median grain size in sediments is relatively complex with a range from 2.5φ to 8φ. The distributions of sorting coefficients in sediments ranging from 1 to 2 are agreed with that of the median grain size. Moreover, it is suggested that sediments of the tidal flats is coarser, better sorted or finer, and worse sorted. The skewness and kurtosis in sediments are ranged from 0.1 to 0.8 and from 1 to 4, respectively. In addition, the distributions of the grain size parameters, including sorting coefficient, skewness and kurtosis in sediments of Chongming Eastern Shoal, Hengsha Eastern Shoal and Jiuduan Shoal are of similar characteristics because there are closely positive correlated relationships among these parameters. However, due to the location difference between Nanhui Southern Shoal and Eastern Shoal, three parameters of grain size in sediments such as sorting coefficient, skewness and kurtosis have relatively large distinctions. Moreover, the tracks of sediment transport can be described based on the distribution of sediments which may reveal sediment transport controlled by the two dominant hydrodynamic factors of current and wave. It is appreciable that coarse sediments with better sorted is subjected to dominant ebb current action and intense wave action resulted from rapidly dissipated wave energy.

关 键 词： 潮滩沉积物 颗粒度 潮流速 波浪 长江口

领　　域： [天文地球] [天文地球] [天文地球] [水利工程]