作　　者： ; ; ;

机构地区： 南京大学地理与海洋科学学院海岸与海岛开发教育部重点实验室

出　　处： 《第四纪研究》 2007年第5期674-689,共16页

摘　　要： 河流是搬运陆源泥沙的主要动力,对相邻的海岸海洋沉积动力有巨大影响。中国河流汇入海洋中的泥沙曾占全球入海泥沙的10%,现代中国边缘海大陆架在晚更新世时曾是海岸平原,河-海交互作用是形成海岸平原与浅海输积泥沙的主要因素。本文选择5个不同类型的河流展示其不同的泥沙运动与河口沉积的特性以及对相邻陆架之影响,包括:1)强潮型动力的鸭绿江河口湾,形成从陆向海与从海向陆的双向水流交汇沉积,海岸形成潮流脊体系。2)季风波浪为主导动力的滦河口,以泥沙的横向运动为主,形成沙坝环绕的双重海岸,沉积粒径自海向陆减小;沿岸浪流携运泥沙向河口两侧分布,使沙坝具有沙咀状的复合特点。3)弱潮型、多沙的黄河口,径流于两侧堆积指状沙咀,沙咀下风侧形成粉砂粘土淤泥湾,沿岸流携运泥沙向渤海湾延伸为淤泥舌。4)径流与沿岸流组合作用的沉积模式,以长江口为代表,泥沙沿岸向南输运为主导,向海岸与向内陆架构成颗粒变细的带状沉积,外陆架出露残留砂。5)充填河口湾的三角洲,以珠江为代表,河流分汊与会潮点泥沙堆积,悬移质扩散至湾外,被沿岸流携带沿海岸向SW运移,外陆架为残留砂沉积。20世纪80年代以来,上述河流均受到人为活动的改造影响,河流自然过程与河海交互作用效应均发生改变。本文主要以滦河三角洲为例阐述河-海交互作用与平原的地貌特征。 Rivers are the major transport agent of terrigenous sediment to the ocean and greatly influence the sedimentary dynamics in coastal water. It is estimated that about 10% of world sediment flux was carried out by rivers from China. The modem continental shelf of China seas was a coastal plain during the Late Pleistocene. River-sea interactivity was the major factor for both the forming of the plain and the distribution of sediments. Five different types of rivers studied in this paper show different characteristics of sediment movement and distribution in estuaries and different influences on their adjacent continental shelf： （ 1 ） The Yalu River, a macro-tidal estuary forms a bidirection （river to sea and sea to river） sediment pattern in the estuary and a tidal ridge along the Yellow Sea coast. （2） The Luanhe River, a river controlled mainly by monsoon waves, forms offshore barriers surrounding the river mouth; as a result, a double-sided coastal line with shallow sea or lagoon between is formed. Sediment pattern shows a decreased grain size deposition from the offshore towards the coast. Coastal waves drive sands to both sides of river mouth, forming the sand barrier with sand spit features. （ 3 ） The Huanghe River, a river controlled by micro-tide, has coarse silt deposited along both sides of the river mouth in the form of finger-shaped bars. The bars grow rapidly with huge amount of sediment transported by the river. On both sides of the bars protect bays in which fine silt and silty clay, collected as fluid mud, are formed. Clayey material is also transported to North as carried by long shore current to the Bohai Bay. （4） The sedimentation pattern of rivers with a combined control of runoff and long shore current, has the Changjiang River as an example. Sediment is mainly deposited at the south, partly to the east. Narrow sedimentary belt is formed with clayey silt, silt, and fine sand of decreasing grain size towards the sea, with a submarine delta formed in 5 - 20m water depth off th

关 键 词： 河海交互作用 沉积模式 黄河口 长江河口 海岸海洋

领　　域： [天文地球] [天文地球]