全新世以来南黄海中部泥质区沉积物的源汇过程及其控制因素

Holocene sediment source-to-sink processes and their controlling factors in the central South Yellow Sea mud area

南黄海中部泥质区沉积了大量来自邻近河流的陆源沉积物,是研究沉积物物源的良好区域,但其沉积物的输运过程和控制因素尚不明确。本文利用南黄海中部泥质区岩芯YSCW-1中沉积物的粒度和元素组成特征,查明自全新世以来研究区沉积物的源汇过程及其控制因素。基于^(14)C放射年龄,YSCW-1岩芯沉积物为9.3 ka以来的沉积,泥质沉积中心形成于约6.5 ka。粒度组成表明研究区沉积物主要由砂、粉砂和黏土组成。基于地球化学相关指标,研究区沉积物来源受到黄河和长江的影响。6.7 ka以前,黄河沉积物占据主导地位;6.7 ka之后长江对南黄海中部泥质区的贡献量增加,可能与黄海现代环流体系的形成有关,海洋锋面限制了黄河以及朝鲜河流沉积物向南黄海中部泥质区的输送。

The central South Yellow Sea mud area is an ideal object for the study of sediment provenance because of the large amount of terrigenous sediments discharged from neighboring rivers.However,the transport processes and controlling factors of these sediments in this area remain unclear.To understand the sediment source-to-sink processes and their controlling factors in the study area since the Holocene,the grain size and element geochemistry of sediments in core YSCW-1 from the mud area were analyzed.The AMS^(14)C ages of core YSCW-1 indicate that the time of deposition is since 9.3 ka,and the formation of the mud depocenter occurred around 6.5 ka.The sediments are mainly composed of sandy silt,clayey silt,and silt.Relevant geochemical indices reveal that,the sediment sources in the study area are mainly from the Huanghe(Yellow)River and the Changjiang(Yangtze)River.Before 6.7 ka,sediments were mainly derived from the Hanghe River.After 6.7 ka,contribution from the Changjiang River increased,which may be related to the establishment of the modern circulation system in the Yellow Sea.Marine fronts may have limited the transport of sediments from the Huanghe River and Korean rivers to the mud area in the central South Yellow Sea.