海洋地质前沿2026，Vol.42Issue(9)：57-66,10.DOI:10.16028/j.1009-2722.2026.012
南海中沙大环礁表层沉积物的粒度特征和输运趋势
Grain size characteristics and transport trends of surface sediments in Zhongsha Atoll,South China Sea
摘要
Abstract
In addition to the growth of hermatypic corals,the accumulation of coral sand is also a significant factor in shaping atoll topography.The grain size of 17 surface sediment samples collected from the shallow wa-ters of the Zhongsha Great Atoll in the South China Sea were analyzed,the seabed-based current was observed at five stations,and the sediment transport trends were also analyzed to understand the erosional and depositional status of the atoll,providing a theoretical basis for the preservation of atoll topography.Results indicate that the sediments consist of three types:gravelly sand,sandy gravel,and sand-bearing gravel,and they were transported via mainly rolling and saltation.In addition,the hydrodynamic environment,the Great Atoll region was divided into three sedimentary environment zones.Zone A(sandy transition zone):Located on the eastern and northwest-ern sides of the outer ring of the Great Atoll,dominated by gravelly sand,representing a high-energy reef flat sedi-mentary environment.Zone B(gravel accumulation zone):Stretching in NW-SE along the Luba Ansha-Manbu Ansha-Haijiu Ansha in the central part of the Great Atoll,composed of chiefly sandy gravels.This zone serves as the primary source of coarse-grained materials for the atoll,indicating rapid,near-source,mixed accumulation processes.Zone C(sand-loss zone):Located at Bohu Ansha in the southwestern part of the Great Atoll,composed of mainly sand-bearing gravel.This zone is characterized by sandy sedimentation and sorting under the influence of strong currents.While hydrodynamics in Zones A and B could transport only a small amount of fine sediments,the maximum current velocity in Zone C could exceed the threshold of sediment motion,resulting in the loss of coral sand.In the future,local monitoring shall be strengthened,and appropriate measures shall be taken to pre-vent sediment loss.关键词
粒度分析/粒度参数/输运趋势/沉积动力/中沙大环礁Key words
grain size analysis/grain size parameters/transport trends/sedimentary dynamics/Zhongsha Atoll分类
海洋科学引用本文复制引用
徐国强,王勇智,杜军,闫文文,李平,周润生..南海中沙大环礁表层沉积物的粒度特征和输运趋势[J].海洋地质前沿,2026,42(9):57-66,10.基金项目
国家科技基础资源调查专项课题"中沙群岛及邻近海域海洋水动力环境调查"(2018FY100102) （2018FY100102）
