广西钦州湾外湾海域表层沉积物粒度特征及沉积环境

沉积物粒度特征是反映沉积作用、沉积环境和沉积动力条件的明显标志,为了解广西钦州湾外湾海域沉积环境,对研究区167组表层沉积物样品进行粒度测定,分析粒度参数特征并划分沉积物类型,运用Pejrup三角投图对研究区进行沉积动力环境分区,采用Gao-Collins粒径趋势分析法总结研究区表层沉积物的运移趋势。结果表明: 研究区表层沉积物以粉砂和砂为主,分选系数差。Folk-Ward分类法的结果显示研究区表层沉积物类型共12种,以砂质粉砂、砂质泥和粉砂分布最广,分别占样品总数的22.16%、17.37%和14.97%。沉积动力分析显示研究区的沉积环境复杂,水动力整体表现出由湾口向外逐渐减弱的特征。粒径趋势分析表明研究区表层沉积物整体向湾口及潮流深槽(航道)方向运移。综合分析表明研究区的沉积环境主要受潮流、波浪及人类活动等的影响。研究成果可为港口建设、深水航道改扩建以及海洋牧场建设等提供科学参考。

Grain size characteristics and sedimentary environment of surface sediments in outer bay waters of Qinzhou Bay in Guangxi

The sediment particle size composition is a clear indicator of sedimentation, sedimentary environment, and sedimentary dynamic conditions. In order to understand the sedimentary characteristics of the outer bay waters of Qinzhou Bay in Guangxi, 167 sets of surface sediment samples were measured for particle size, and analyzed for particle size parameter characteristics to divide the sediment types. The Pejrup triangle map was used for the partition of the sedimentary dynamic environment of the outer bay waters of Qinzhou Bay, and Gao-Collins particle size trend analysis method was used to summarize the migration trend of surface sediments in the study area. The results show that the surface sediments in the outer bay waters of Qinzhou Bay is mainly composed of silt and sand, with poor sorting ability. According to the Folk-Ward classification method, the authors divided the surface sediments in the outer bay waters of Qinzhou Bay into 12 types, and sandy silt, sandy mud and silt were the most widely distributed, accounting for 22.16%, 17.37%, and 14.97% of the total sample size, respectively. The analysis of sedimentary dynamics indicates that the sedimentary environment in the study area is complex, and the hydrodynamic forces is strong, which are generally characterized by a gradual weakening outward from the bay mouth. The trend analysis of particle size indicates that the sediment in the study area migrates towards the bay mouth and tidal deep channel (channel) as a whole. Comprehensive analysis shows that the sedimentary environment in the study area is mainly influenced by tidal currents, waves, and human activities. The research results could provide scientific references for port construction and the expansion of deepwater waterways.