地理学报 ›› 2009, Vol. 64 ›› Issue (5): 629-637.doi: 10.11821/xb200905012

• 地表环境 • 上一篇    

长江口拦门沙河段潮滩表层沉积物分布特征

闫虹,戴志军,李九发,赵建春,张小玲   

  1. 华东师范大学河口海岸学国家重点实验室,上海200062
  • 收稿日期:2008-12-05 修回日期:2009-03-03 出版日期:2009-05-25 发布日期:2010-08-03
  • 通讯作者: 戴志军,E-mail: zjdai@sklec.ecnu.edu.cn E-mail:zjdai@sklec.ecnu.edu.cn
  • 作者简介:闫虹(1984-),女,硕士生,主要从事河口海岸泥沙运动等方面的研究。E-mail: hongy0031@163.com
  • 基金资助:

    上海市科委项目(07DJ14003);上海市科技启明星项目(06QA14016);河口海岸学国家重点实验室科研业务 费资助(2008KYQN03)

Distribution of Surficial Tidal Flat Sediments in the Yangtze Estuary

YAN Hong,DAI Zhijun,LI Jiufa,ZHAO Jianchun,ZHANG Xiaoling   

  1. State Key Lab. of Estuarine and Coastal Research,East China Normal University,Shanghai 200062,China
  • Received:2008-12-05 Revised:2009-03-03 Online:2009-05-25 Published:2010-08-03
  • Supported by:

    Natural Science Foundation of Shanghai,No.07DJ14003;Foundation of Ministry of Science and Technology of China,No.SKLEC-2008KYQN03;Shanghai Youth Science and Technology Venus Program,No.06QA14016

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。

关键词: 潮滩沉积物, 颗粒度, 潮流速, 波浪, 长江

Abstract:

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 river 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. In addition, due to the effects of obstructed branches, guided current and broken wave actions of the Deep Water Channel Project, grain size in sediments located on two sides of the groyne is of uneven distribution characteristics.

Key words: tidal flat sediments, particle sizes, current velocity, wave, Yangtze Estuar