| 摘要: |
| 河流入海泥沙的大部分主要分布在河口、三角洲及近岸陆架地区，发育一系列的粗颗粒沉积体系，是海砂资源重要分布区。本文以福建闽江口为研究对象，初步探讨了沉积物输运过程及海砂资源的形成机制。观测结果表明，闽江河口水体盐度由河口内部向口外海域逐渐增大，水体浊度总体减小；闽江河口附近海域近底部（距离海底25cm）流向表现出一定的旋转流特征，潮周期内余流表现为向海输运，而推移质输运主要发生在涨潮期间，并且潮周期内净向陆输运。表层沉积物粒度分析结果表明，闽江河口水下三角洲前缘表层沉积物主要由粗颗粒物质组成，沉积物类型以砂和砂质粉砂为主，中值粒径小于4φ；前三角洲地区表层沉积物主要由细颗粒物质组成，中值粒径介于4φ—6φ之间。沉积物粒径趋势分析结果表明，闽江入海泥沙经梅花水道和长门水道入海后，在盐淡水混合、径流、潮流的作用下，在闽江河口形成了四个粗颗粒沉积物汇聚区，成为闽江口地区海砂资源的重要分布区；而细颗粒物质在河口羽流和潮流的作用下向偏东方向输运，形成了以黏土质粉砂为主的前三角洲。 |
| 关键词: 海砂资源 河口羽状流 潮流 沉积物输运 闽江口 |
| DOI：10.11693/hyhz20200100024 |
| 分类号: |
| 基金项目:国家自然科学基金项目，41776099号；自然资源部第三海洋研究所基本科研业务费项目，海三科2017015号，海三科2019018号 |
附件 |
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| SEDIMENT TRANSPORT IN MINJIANG RIVER ESTUARY AND ADJACENT SHELF AREA AND ASSOCIATED RESOURCE EFFECT |
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WANG Ai-Jun, YE Xiang, LAI Zhi-Kun, WANG Liang
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Laboratory for Coast&Ocean Geology, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
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| Abstract: |
| Most of sediment delivered by river distributed mainly in river mouth, deltas, and coastal shelf areas, forming a series of coarse-grained deposits that are important resources of marine sands. In this study, the mechanism of sediment transportation of the sand resources in the Minjiang River estuary in SE China was studied. Observation showed that with the seaward increase in salinity in the estuary area, the water turbidity decreased in overall. In addition, the current flow direction near the bottom (25cm above the bed) in the estuary is rotatary; the bottom residual current flowed seaward, and the bedload transport occurred mainly during the flood tide and the net transport took place landward over the entire tidal cycle. The grain-size analysis of surface sediments showed that the surface sediments in the subaqueous delta front of the Minjiang River estuary are composed of mainly coarse-grained sediments, such as sand and sandy silt; the median grain size is less than 4φ. The surface sediments in the prodelta are mainly composed of fine-grained sediment in median grain size of 4φ—6φ. In addition, the grain size trend analysis show that when the sediments are discharged from the Minjiang River into the sea through Meihua Channel and Changmen Channel, due to salt and fresh water mixing under runoff and tidal current, four coarse-grained sediment convergence areas are formed in the estuary which are important marine sands resources. However, under complicated effects of river plume and tidal current, fine-grained sediments represented by clayey silts are transported eastward in overall to form the prodelta. |
| Key words: marine sand resource river plume tidal current sediment transport Minjiang River estuary |
