广西钦州湾海域表层沉积物分异特征与规律

Sediment characteristics and differentiation in the Qinzhou Bay, Guangxi, China

根据2008年12月广西钦州湾海域表层沉积物粒度分析结果,结合沉积物结构、地形和水动力条件,探讨了沉积物的分布规律及其作用机制。结果表明,钦州湾海域表层沉积物在横向上,自西向东呈现出西部粗、东部细,分选程度西部好于东部的特征;在纵向上,沉积物粒径呈现由内向外粒径从粗到细的特征,大致在5m水深处存在一个明显的界限,该水深以浅区域的砂含量较高,且主要沉积砂等较粗物质;该水深以深区域以粉砂质黏土为主,砂含量较低。Flemming的三角图式表明,钦州湾海域沉积动力相对较弱。在此基础上,根据水动力差异与物源不同,将研究区划分为5m水深以浅的西部区、5m水深以浅的东部区和5m水深以深的区域等3个沉积区。

The authors investigated the sedimentary environments and their hydrodynamic processes in the Qinzhou Bay, based on the data of surface sediment samples collected in 2008 in combination with sediment texture, topography, and hydrodynamics of the bay. The results indicate that transversal distributions of surface sediments in the outer bay are from coarse to fine particle size, and the degree of the sort is from good to poor level. For the longitudinal distribution of surface sediments, there is a large percentage of sand at the underwater slope that is shallower than 5 m; however, slit and clay predominate at the underwater slope that is deeper than 5 m. According to the differences in hydrodynamic, morphologic features, and sediment sources, the outer bay can be divided into three main sedimentary zones.