莱州湾西南部表层沉积物粒度分布特征及其现代沉积环境分区

DISTRIBUTION OF SURFACE SEDIMENTS AND MODERN SEDIMENTARY ENVIRONMENT IN THE SOUTHWESTERN LAIZHOU BAY

根据莱州湾西南部207个表层沉积物样品的粒度分析结果,对莱州湾西南部沉积物粒度分布特征进行了研究,在此基础上应用系统聚类分析方法并结合物源及水动力条件探讨了其现代沉积环境分区。结果表明,研究区表层沉积物类型以粉砂质砂、砂质粉砂和粉砂为主,分布范围最广的粉砂主要位于淄脉沟以北;沉积物平均粒径由近岸向莱州湾中部逐渐变细,从南向北呈现粗—细—粗的变化趋势;研究区现代沉积环境分为高能粉砂质砂粗粒沉积区、砂质粉砂过渡沉积区以及低能粉砂细粒沉积区,其水动力环境表现为波浪作用逐渐减弱,潮流作用逐渐增强,沉积物物源由近岸河流、岸滩侵蚀来沙为主变为以黄河悬浮—再悬浮物质为主。

Based on the grain size data of 207 surface sediment samples in the southwestern Laizhou Bay,the distribution pattern of surface sediments is studied.The method of cluster analysis is applied to exploring its modern sedimentary environments with the help of source and hydrodynamic analysis.Results show that the surface sediments in the study area are characterized by silty sand,silt and sandy silt,and silt is widely distributed in the sea area north to the Zimai Gou.The mean grain size gradually decreases from the shore to the central part of the Laizhou Bay,while it shows a coarse-finecoarse trend from south to north.The modern sedimentary environment in the study area can be divided into 3zones：the high-energy silty sand depositional zone,sandy silt transitional zone and low-energy silt depositional zone.In terms of hydrodynamic environment,it presents a trend of the weakening of wave action as tidal currents are strengthened.At the same time,the source of sediments changes from rivers and beach erosion to suspension and resuspension of the Yellow River deposits.