闽江河口水下三角洲及周边海域现代沉积环境演化及其对人类活动的响应  

Contemporary Sedimentary Environment Evolution and Its Response to Human Activities in the Minjiang Subaqueous Delta and Surrounding Waters

作　　者：谢津剑 王爱军 叶翔 陶舒琴 蔡枫 XIE JinJian;WANG AiJun;YE Xiang;TAO ShuQin;CAI Feng(School of Civil Engineering,Fuzhou University,Fuzhou 350108,China;Laboratory of Coastal and Marine Geology,Third Institute of Oceanography,Ministry of Natural Resources,Xiamen,Fujian 361005,China;Fujian Provincial Key Laboratory of Marine Physical and Geological Processes,Xiamen,Fujian 361005,China)

机构地区：[1]福州大学土木工程学院,福州350108 [2]自然资源部第三海洋研究所海洋与海岸地质研究室,福建厦门361005 [3]福建省海洋物理与地质过程重点实验室,福建厦门361005

出　　处：《沉积学报》2024年第2期558-574,共17页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(UZZA20585,41776099);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,海三科2019018)。

摘　　要：【目的】河口三角洲是陆海相互作用的敏感地带,也是人类活动最为频繁的地区,研究人类活动对河口三角洲演化的影响,一直以来都是国际沉积学的研究重点和热点。【方法】以福建闽江河口水下三角洲为研究对象,通过水动力模拟和表层沉积物粒度分析,探讨了闽江河口水下三角洲及周边海域现代沉积环境演化。【结果与结论】研究区河口内潮流以往复流为主,在口外海域逐渐转变为旋转流,水下三角洲地区流速大,外海流速较小;沉积物类型以砂、粉砂和砂质粉砂为主,平均粒径平均值分别为1.57Φ、6.78Φ和5.62Φ,并且由河口向口外陆架方向沉积物粗颗粒组分含量逐渐减少,细颗粒组分含量逐渐增大;沉积物输运趋势显示,在闽江河口水下三角洲内,沉积物输运呈现向东、东南和东北方向,在口外海域沉积物呈现朝东南和东北离岸方向,以及向西北朝岸方向输运;基于粒度组成、粒度参数及站位水深多元统计分析,综合地理位置、沉积物源和水动力条件,将研究区现代沉积环境划分为4个沉积区;通过探讨不同控制因素下的河口水下三角洲沉积环境差异,揭示了不同沉积区的沉积环境对人类活动的响应。该研究结果可为河口资源开发和生态环境保护提供科学依据。[Objective]River deltas are sensitive areas of land-sea interaction with intense human activities,and continue to be the focus of international research.[Methods]Based on grain-size analysis of surface sediments in the Minjiang River delta and surrounding waters,this study discusses the evolution of the contemporary sedimentary environment in the area.[Results]It is shown that the dominant to-and-fro tidal current within the estuary gradually changes into a rotating seaward flow,and that the current speed decreases from the subaqueous delta to the offshore area.The sediments in the study area are mainly sand,silt and sandy silt,with mean grain-sizes of 1.57Φ,6.7Φand 5.62Φ.From the estuary to the adjacent coastal shelf area,coarse-particle content decreases and fine-particle content gradually increases.In addition,grain size trend analysis indicates that the sediment delivered by the Minjiang River is transported towards the E,SE and NE when it enters the estuary.After the fine sediment passes through the subaqueous delta,it tends to be transported offshore towards the SE and NE.A multivariate statistical analysis of sediment composition,grain size parameters and water depth integrating the geographical location,sediment source and hydrodynamic conditions indicate that the contemporary sedimentary environment in the study area is divided into four sub-sedimentary districts.The study reveals the effect of different influences on the sedimentary environment and demonstrates its response to human activities.[Conclusions]The results of this study provide advice for estuary resource development and ecological environment protection.

关 键 词：水下三角洲 闽江河口 粒度参数 沉积物输运趋势 沉积环境 

分 类 号：P736.2[天文地球—海洋地质]