摘要
对山东半岛泥质楔柱状样进行沉积物粒度分析,并在210Pb测年基础上结合黄河年输沙量、悬浮泥沙粒径、河口位置及沿岸流强弱替代指标等数据研究近百年来黄河改道及输沙量变化对远端沉积区沉积特征的影响。研究结果显示,研究区沉积物粒度的变化是黄河入海泥沙特征和沿岸流等水动力作用共同影响的结果。1884–1939年及1947–1999年,研究区沉积物粒度特征的变化主要受到沿岸流强弱的影响;1939–1947年及1999–2012年,受1938–1947年花园口决堤以及20世纪90年代末以来黄河年输沙量持续偏低致使源区泥沙不足的影响,沉积物粒度相对粗化,与沿岸流强度的相关性减弱。与黄河入海泥沙近端沉积区不同,研究区粒度特征对黄河尾闾改道事件不敏感,且对花园口决堤及年输沙量低于临界值的响应有一定程度的延迟,这与该区沉积物经历了再悬浮过程及中间复杂的物质混合有关。黄河改道及输沙量变化仍然是远端沉积区沉积特征演化不可忽视的因素。
In this study, sediment grain size of a core retrieved from Shandong mud wedge has been tested. On the basis of 210 Pb dating, the impacts of channel shifts and changes of annual sediment load of the Yellow River on the sedimentary characteristics of the remote depositional zone over the past 100 years have been studied by analyzing the temporal changes of grain size in the core, Yellow River’s annual sediment load, particle size of suspended sediment in the lower reaches of the Yellow River, Yellow River estuary location, and replacement index of coastal current intensity. The results show that grain size of sediments in the study area is affected by characteristics of sediments input of the Yellow River and strength of coastal hydrodynamics. During the period 1884-1939 AD and1947-1999 AD, the variation of grain-size characteristics in the area was mainly affected by strength of the coastal current. During the period 1939-1947 AD and 1999-2012 AD, sediments in this area were obviously coarsened,and their correlation with the coastal current intensity weakened. Such a coarsening trend of sediment is likely attributed to the insufficient sediment input of the Yellow River, because the Yellow River was cut down at the Huayuankou during 1938-1947 AD and the annual sediment load of the Yellow River was continuous lowering since the end of the 1990 s. Different from proximal depositional zone, grain-size characteristics of this remote offshore depositional area was not sensitive to the channel shifts in the lower reaches of the Yellow River. A certain delay also existed in the response of sediment grain size to the reduction of annual sediment load. The reason was that sediment in this area was subjected to resuspension and complex material mixing. Channel shifts of the Yellow River and change of sediment load were still factors that could not be ignored for evolution of sedimentary characteristics of remote depositional zone.
作者
杨立建
马小川
贾建军
阎军
栾振东
Yang Lijian;Ma Xiaochuan;Jia Jianjun;Yan Jun;Luan Zhendong(Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;University of Chinese Academy of Sciences,Beijing 100049,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China)
出处
《海洋学报》
CAS
CSCD
北大核心
2020年第1期78-89,共12页
基金
河口海岸学国家重点实验室开放基金资助课题（SKLEC-KF201804）
国家自然科学基金（41876035）
中国科学院战略先导专项(XDA11030301)
关键词
粒度
端元组分
山东半岛泥质楔
黄河
输沙量
改道
grain size
end-members modelling
the Shandong mud wedge
Yellow River
sediment load
channel shifts
