湛江海区海岛潮间带表层沉积物特征及对沉积环境的指示

为全面揭示潮滩沉积物粒度数据中蕴含的水动力环境信息以及水搬运方式与粒径的对应关系,采用了C-M图解、粒度累积曲线、R型聚类分析和R型因子分析等方法,对湛江海区海岛136个潮间带表层沉积物粒度样品进行综合分析。结果表明,弱水动力沉积的细粒组分含量稳定,受海水扰动影响,粗粒组分含量不稳定;C-M图解、粒度累积曲线及因子分析反映的水动力环境一致,潮间带主要有三种沉积物搬运方式:悬移、推移和跃移,悬移对应的粒径为5φ~>11φ;推移对应的粒径为<1φ~1φ;跃移对应的粒径为2φ~4φ。因此,潮间带对沉积物粒度特征的综合分析能较好地指示水动力环境。

The grain-size characteristics and their environmental indications of the island intertidal surface sediments of Zhanjiang offshore area

In order to elucidate the hydrodynamic force from grain-size data of intertidal zone sediment and the corresponding relationship between sediment grain-size and hydrodynamic transport modes,136 sediment grain-size samples that collected from 29 islands of Zhanjiang offshore area were analyzed.Several research tools,including C-M graph,grain-size cumulative curves and factor analysis,were introduced to analyze the grain-size data.The clustering analysis indicates that the content of fine fractions is stable;in comparison,that of coarse fractions is unstable.The fine fractions are deposited on the condition of weak hydrodynamics and the coarse correspondences are generated by sea-water disturbance.Two transport ways,suspension and saltation,are recognized through C-M graph and grain-size cumulative curves.The same conclusions are obtained from three analysis of C-M graph,grain-size cumulative curves and factor analysis.Three principal transport modes,suspension,displacive precipitation and saltation,affect intertidal sediment deposit,are corresponding to,respectively,the grain-size range of 5φ to larger than 11φ,of –1φ to 1φ and of 2φ to 4φ.Therefore,intertidal sediment grain size can be applied soundly to discuss the hydrodynamic environment.