渤海湾西南部海域表层沉积物分布特征

THE DISTRIBUTION PATTERN OF SURFICIAL SEDIMENTS IN SOUTHWEST BOHAI BAY

基于渤海湾西南部海域3次表层沉积物调查资料,通过表层沉积物粒度数据研究沉积物类型和分布特征,在空间和时间尺度上探讨沉积物变化规律。结果表明:研究区表层沉积物主要以砂质粉砂和黏土质粉砂为主,西北部沉积物较细,东南部沉积物相对较粗,深水区沉积物较细,浅水区沉积物相对较粗;研究区浅水区分选性好于深水区,东南部分选性好于西北部;研究区偏态总体为近对称或正偏;对比3次沉积物中值粒径,沉积物在时间序列上具有变细的趋势。

Bottom sediments acquired from the three surveys in the southwest Bohai Bay were studied for the types of surficial sediments and their temporal and spatial distribution pattern. It is revealed that the surficial sediments in the studied area are mainly composed of sandy silt and clayey silt. They are fine in the northwest, and coarser in the southeast. As far as vertical distribution is concerned, they are fine in deep-water and coarser in shallow-water. Sorting of the sediments shows a similar pat- tern, i.e. being higher in shallow-water but lower in deep-water,or being higher in the southeast of the study area; The skewness of the sediments shows that the distribution of sediments is symmetrical or nearly symmetrical in the study area. Comparison of the mean size from the three times of survey indicates that the sediments were getting finer with time.