| 摘要: |
| 本文通过对长江口北槽深水航道中部（湾顶）南、北导堤两侧坝田区域所采浅钻柱状样的沉积物特征、粒度参数特征、粒度成分和沉积速率特征等的分析，探讨北槽深水航道水动力条件和泥沙沉积环境。结果显示，柱状样以粘土质粉砂为主，受径流和潮汐作用，分选性都较差，偏态均为正偏，北导堤和南导堤两侧柱状样的分选系数、偏态和峰态在同一侧相互之间的特征较一致，南北两边三组分组成接近；南北两侧的差异较为明显，北导堤一侧的平均粒度比南导堤的小，北导堤坝田附近的柱状样粒级百分比在垂向上波动变化较大，南导堤则表现的较为单一；南北导堤的敏感组分主要集中在粒级100 μm部分。结合资料和测年数据，综合得出，由于北导堤和南导堤的涨落潮不对称，导致了南北在粒度特征上的不同；南北导堤两侧的泥沙来源较为一致，大部分为非流域来沙；北槽受深水航道工程影响巨大，泥沙沉积过程复杂，还需深入研究。 |
| 关键词: 长江口 北槽 沉积 柱状样 粒度 |
| DOI： |
| 分类号:P736.21 |
| 基金项目:自然科学基金项目(41276080, 51320105005)，水利部公益项目（201201070-03） |
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| Sediment depositional characteristics of North Passage in Yangtze River Estuary |
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Deng Zhirui,He Qing,Xing Chaofeng and Guo Leicheng
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State Key Laboratory of Estuarine and Coastal Research,State Key Laboratory of Estuarine and Coastal Research,State Key Laboratory of Estuarine and Coastal Research,State Key Laboratory of Estuarine and Coastal Research
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| Abstract: |
| We got the sediment depositional process information by analyzed some grain size parameters such as mean grain size, components, standard deviations, sedimentation rates, and discussed the hydrodynamic and depositional environment of the north passage in Yangtze River Estuary. The results showed that, clayey silt was major constituent, the sorts of the sediments are all poor and skewness is positive due to the strong influence of the action of runoff and tide. The cores skewness and kurtosis coefficients relatively appeared consistent characteristics on the same side either the North Jetty or South jetty but the distinction between North and South was evident as a result of discriminate hydrodynamics. The mean grain size of North Jetty was smaller than South Jetty and the three components was similar in both sides, nevertheless the grading curve that in North Jetty changes vertical are more substantial than South Jetty. 100 micron grain size was the sensitive component in both sides. Based on the document to date and isotope dating, we known that sediment source of North-South Jetty was consistent, most of which are not from river basin, and due to tidal asymmetrical, North Jetty and South Jetty had difference in grain-size characteristics. Under the deep-water channel project impact, sediment deposition process was complex therefore more in-depth study was required. |
| Key words: Yangtze River Estuary sediment depositional core sediments grain size |