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| 闽粤交界处大埕湾海域表层沉积物分布运移特征及沉积动力环境分区 |
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林纪江1,2, 王平1,2, 余世维3, 栾虹4, 范哲南1,2, 牛建伟5, 郑兆勇2,6
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1.国家海洋局南海信息中心, 广东 广州 510310;2.自然资源部海洋环境探测技术与应用重点实验室, 广东 广州 510310;3.广东省海洋发展规划研究中心, 广东 广州 510220;4.国家海洋局南海标准计量中心, 广东 广州 510310;5.中国科学院南海海洋研究所, 广州 510301;6.国家海洋局南海规划与环境研究院, 广东 广州 510310
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| 摘要: |
| 大埕湾位于闽粤交界处,是典型的岬角弧形开放型海湾,本文基于实测的海流、表层沉积物数据,分析了大埕湾海域表层沉积物的分布特征,计算了再悬浮通量与输运通量,结合粒径趋势分析方法探讨了表层沉积物运移趋势,利用Flemming三角图示法对沉积动力环境进行分区并分析了泥沙输运的主要控制因素。结果表明,研究区表层沉积物有砂质粉砂、粉砂、含砾泥和泥4种类型,沉积物颗粒较细,整体以粉砂和泥为主,砂质粉砂和含砾泥呈圆斑状零星分布;粒级组分含量和粒度参数平面分布分区明显,黏土组分、分选系数和偏态值呈现“东北小西南大”的特点,粉砂组分和峰态值则表现出相反趋势。观测期间表层沉积物日再悬浮量为41.86 kg/m2,日净输运通量40.36 kg/m,逐时再悬浮通量值和单宽输沙率大小与潮流流速变化相关性较好,且涨潮段大于落潮段,净输沙指向涨潮方向,由西南向东北方向输沙。研究区沉积动力环境可划分为DⅡ、EⅡ和EⅢ 3个分区,沉积物搬运以悬移为主,潮流和波浪是研究区泥沙起动及输运的主要动力,泥沙来源主要有近岸侵蚀供沙、东西两侧海域输沙以及少量短源季节性陆源碎屑补给3方面。 |
| 关键词: 分布特征 输运通量 运移趋势 沉积动力分区 大埕湾 |
| DOI：10.11759/hykx20220527001 |
| 分类号:P736.21 |
| 基金项目:广东省海洋经济发展专项(GDNRC[2020]050);2020年国家重点研发计划重点专项(2019YFC1408400) |
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| Distribution and migration characteristics of surficial settlements and division of dynamic sedimentary environment in Dacheng Bay between Fujian and Guangdong |
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LIN Ji-jiang1,2, WANG Ping1,2, YU Shi-wei3, LUAN Hong4, FAN Zhe-nan1,2, NIU Jian-wei5, ZHENG Zhao-yong2,6
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1.South China Sea Information Center, SOA, Guangzhou 510310, China;2.Key Laboratory of Marine Environmental Detection Technology and Application, MNR, Guangzhou 510310, China;3.Research Centre for the Marine Development and Planning of Guangdong Province, Guangzhou 510220, China;4.South China Sea Standard Metrology Center, SOA, Guangzhou 510310, China;5.South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;6.South China Sea Institute of Planning and Environmental Research, SOA, Guangzhou 510310, China
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| Abstract: |
| Dacheng Bay is a typical cape arc open bay located between Fujian and Guangdong. Based on the measured current and surficial settlement data, this study analyzes the distribution characteristics of the surficial settlement in Dacheng Bay. Moreover, it discusses the transport trend of the surficial settlement by calculating the resuspension and transport flux and combined with the particle size trend analysis method. Furthermore, it partitions the dynamic sedimentary environment using Flemming’s triangle graphical method and analyzes the main control factors of sediment transport. The results show four types of surficial settlements in the study area: sandy silt, silt, gravelly mud, and mud. The sediment particles are fine and mainly consist of silt and mud; moreover, sandy silt and gravelly mud are distributed sporadically in round spots. The plane distribution zoning of the component content and parameters of the particle size is obvious. The clay component, sorting coefficient, and skewness values are small and large in the northeast and southwest, respectively, whereas the silt component and peak value show the opposite trend. During the observation period, the daily resuspension amount of surficial settlement was 41.86 kg·m-2 and the daily net transport flux was 40.36 kg·m-1. The hourly resuspension flux and sediment transport rate per unit width correlate well with the variation in tidal current velocity, and the rising tide section exceeds the falling tide section. The net sediment transport points to the rising tide direction and transports sediment from the southwest to the northeast. The dynamic sedimentary environment of the study area can be divided into three zones: DⅡ, EⅡ, and EⅢ. The sediment transport is mainly suspended. Tidal currents and waves are the main driving forces for sediment initiation and transport in the area under study. The sediment sources mainly include nearshore erosion and sediment supply, sediment transport from the East and West seas, and a small amount of short source seasonal land-based debris supply. |
| Key words: distribution characteristics transport flux migration trend sedimentary dynamic division Dacheng Bay |
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