摘要
对2013年8月在海南新村港潟湖采集的表层沉积物样品进行粒度分析,揭示了该区表层沉积物的粒度特征和沉积物类型,结合高空间分辨率的水动力和水深数据,采用系统聚类和主成分相结合的方法划分现代沉积环境。结果表明,研究区表层沉积物主要有4种类型,以粉砂和粉砂质砂为主,分别分布在潟湖中部和近岸浅水区域。沉积物平均粒径变化较大（0～8.0Ф）,均值为4.6Ф,沉积物随水深增大而逐渐变细;沉积物粒度组分以砂（平均含量43%）和粉砂（平均含量为52%）为主,黏土含量较少,平均含量为5%。聚类结果表明,平均粒径可分为两组：第一组平均粒径均大于5.5Ф,均值为6.8Ф;而第二组平均粒径均小于3.5Ф,均值为2.2Ф。此外,平均粒径与分选、偏态和峰态系数之间呈现出两种不同的相关关系。研究区大潮和小潮期间的均方根流速（RMSV）均值是7.5和6.9cm/s,标准偏差分别是15.3和14.9cm/s。当RMSV大于4cm/s,RMSV与极细砂（63～125μm）含量呈明显的正相关关系,这表明RMSV决定了潟湖沉积物中极细砂含量。聚类和主成分分析结果表明,平均粒径、峰态和分选系数是对沉积环境最为敏感的粒度参数组合,同时结合高空间分辨率的水动力和水深数据,将研究区沉积环境划分为3类。这样划分充分考虑了水动力、物源、地形及其相互作用,更能有效地揭示沉积环境的差异,尤其体现了适宜的粒度参数组合和高空间分辨率的水动力数据在沉积环境划分中的重要性。
Surface sediment samples were collected from the lagoon of Xincun,Hainan Island in China during August2013,investigating grain size distribution pattern and sediment types.Furthermore,modern sedimentary environment can be well classified by grain size parameters,water depth and hydrodynamic conditions using system cluster and principal component analysis（PCA）.The result indicates that sediment samples are characterized by silt and silty sand,which distribute in the central lagoon and near-shore shallow water area,respectively.The mean grain size varies from 0to 8Ф,with an average value of 4.6Ф.The silt has the highest content with 52%in average,and the average content of sand and clay is 43%and 5%.A significant relationship was found between the mean grain size and water depth,which suggested that surface sediment becomes finer gradually with increasing water depth.There are two groups based on cluster analysis of grain size data：the mean grain size of group 1is more than 5.5Ф,with an average value of 6.8Ф,whereas the mean grain size of group 2is composed of less than 3.5Ф,with an average value of 2.2Ф.Furthermore,there are also two different relationships between the mean grain size and sorting/skewness/kurtosis.The average value of root mean square velocity（RMSV）is 7.5cm/s and6.9cm/s during spring and neap tide;standard deviation is 15.3cm/s and 14.9cm/s,respectively.There is a significant positive relationship between very fine sand fraction（63to 125μm）and RMSV when RMSV4cm/s.The results suggested that RMSVdetermines the variability of very fine sand fraction in the lagoon.System cluster and PCA were used to identify the proper grain size parameters associated with mean grain size,kurtosis,and sorting.Therefore,the modern sedimentary environment can be well classified into three types using mean grain size,kurtosis,sorting,high-spatial resolution RMSVand water depth.In particular,the results suggest the importance of proper grain size parameters and high-spatial resolution hydrodynamic data in differentiate the coastal sedimentary environments.
出处
《海洋学报》
CAS
CSCD
北大核心
2016年第1期94-105,共12页
基金
国家自然科学基金重点项目--海岸风暴频率-强度关系的沉积记录分析(41530962)
关键词
表层沉积物
粒度
沉积环境
聚类分析
主成分分析
均方根流速
数值模拟
新村港潟湖
surface sediment
grain size
sedimentary environment
cluster analysis
PCA
root mean square velocity
numerical simulation
the lagoon of Xincun
