王伟,汤世凯,胡艳萍,等. 山东半岛南部丁字湾口外海底沉积物粒度时空变化及影响因素[J]. 海洋地质与第四纪地质,2022,42(2): 70-80. doi: 10.16562/j.cnki.0256-1492.2021050601
引用本文: 王伟,汤世凯,胡艳萍,等. 山东半岛南部丁字湾口外海底沉积物粒度时空变化及影响因素[J]. 海洋地质与第四纪地质,2022,42(2): 70-80. doi: 10.16562/j.cnki.0256-1492.2021050601
WANG Wei,TANG Shikai,HU Yanping,et al. Spatio-temporal variation and influencing factors of seafloor sediment grain size off the mouth of Dingzi Bay of Southern Shandong Peninsula[J]. Marine Geology & Quaternary Geology,2022,42(2):70-80. doi: 10.16562/j.cnki.0256-1492.2021050601
Citation: WANG Wei,TANG Shikai,HU Yanping,et al. Spatio-temporal variation and influencing factors of seafloor sediment grain size off the mouth of Dingzi Bay of Southern Shandong Peninsula[J]. Marine Geology & Quaternary Geology,2022,42(2):70-80. doi: 10.16562/j.cnki.0256-1492.2021050601

山东半岛南部丁字湾口外海底沉积物粒度时空变化及影响因素

Spatio-temporal variation and influencing factors of seafloor sediment grain size off the mouth of Dingzi Bay of Southern Shandong Peninsula

  • 摘要: 对丁字湾口外浅海区平行海岸线及垂直海岸线方向上的11个柱状沉积物进行了粒度和210Pb放射性活度测试,分析了沉积物类型和粒度参数变化特征并计算了沉积速率,结合丁字湾地貌演变、流域人类活动变化,分析了人类活动对丁字湾口外滨海段沉积物粒度演变的影响。海底柱状沉积物可划分7种类型,水平方向上平均粒径Φ值从三角洲中心向四周整体呈现逐渐增大的趋势,垂直方向上平均粒径Φ值呈现不规则变化特征。沉积物分选性属于较好—中等,偏态为近对称—正偏,峰态为尖锐。不同沉积物类型及特征参数揭示沉积时期相应的水动力环境,砂、含砾砂和粉砂质砂及其较小的平均粒径Φ值揭示相对较强的水动力环境,砂质粉砂、粉砂、黏土和泥及其较大的平均粒径Φ值揭示了相对较弱的水动力环境。受不同水动力环境影响,三角洲顶端和前缘平均沉积速率分别为0.51和1.19 cm/a。与1980年前相比,1980年以后人类对滩涂围垦等活动影响强度加大,海湾纳潮空间、入海泥沙流量和流速均减小,在人类影响范围区域内的沉积物颗粒具有总体向上变细的趋势。

     

    Abstract: 11 columnar sediment samples are collected off the mouth of Dingzi Bay for grain size analysis and 210Pb radioactivity measurement. With the results, the sediments are classified and grain size parameters and sedimentation rate calculated. Combined with the geomorphologic evolution of Dingzi Bay and the change in human activities in the Wulong River Basin, the influence of human activities on the evolution of sediment grain size in the coastal section out the Wulong River estuary is discussed. The results suggested that the columnar sediments may be divided into seven types, and the mean grain size (Φ) in the horizontal direction shows a trend of increase from the deltaic center to all directions as well as an irregular pattern in vertical direction. The sediment sorting changes from good to medium, with a near-symmetric-positive skewness and sharp kurtosis. Sediment types and their diagnostic parameters may be used as tools to reveal depositional environments. Sand, gravelly and silty sand and their small Φ-values suggest relatively strong hydrodynamic environments, while sandy silt, silt, clay and mud and their large Φ-values indicate relatively weak hydrodynamic environments. The average sedimentation rate at the top and front of the delta was 0.51 cm·a−1 and 1.19 cm·a−1, respectively. Human activities in beach reclamation and others increased since 1980, which have caused the decrease in tidal space, sediment discharge and velocity into the sea. As the results, the overall trend of sediment particles in the human-influenced area becomes finer.

     

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