中全新世以来南黄海中部沉积过程——基于岩心粒度和有机质指标  

Sedimentary processes of central South Yellow Sea since the mid-Holocene based on grain size and organic matter indexes

作　　者：皮仲 李铁刚 类彦立[1,3,4] Pi Zhong;Li Tiegang;Lei Yanli(Department of Marine Organism Taxonomy&Phylogeny,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Key Lab of Marine Sedimentology and Environmental Geology,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;University of Chinese Academy of Sciences,Beijing 100049,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China;Laboratory for Marine Geology,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266061,China)

机构地区：[1]中国科学院海洋研究所,山东青岛266071 [2]自然资源部第一海洋研究所海洋沉积与环境地质国家海洋局重点实验室,山东青岛266061 [3]中国科学院大学,北京100049 [4]中国科学院海洋大科学研究中心,山东青岛266071 [5]青岛海洋科学与技术试点国家实验室海洋地质过程与环境功能实验室,山东青岛266061

出　　处：《海洋学报》2019年第11期75-88,共14页

基　　金：国家自然科学基金（41476043,41976058,41830539）;青岛海洋科学与技术国家实验室鳌山科技创新计划项目（2016ASKJ13）

摘　　要：海陆交互作用下的南黄海沉积环境复杂,其沉积机制一直是古海洋研究的重点和难点。本文以取自南黄海中部泥质区的Z1岩心为载体,对196个样品的粒度和整体有机质指标(TOC、TN、TOC/TN和δ13Corg)进行了详细分析,并对5个层位进行AMS14C年龄测定,分辨率高达11 a/cm。研究结果显示,6.1 ka BP以来南黄海中部沉积过程可分为3个阶段:(1)6.1~5.2 ka BP,沉积物粒度较粗,以残留砂和陆源粗粒物质为主,有机质含量较低且主要为陆源输入,本阶段多受东亚季风强盛的影响,动荡海洋环境下有机质保存效率低,大量陆源输入冲淡作用显著;(2)5.2~3.9 ka BP,沉积物粒度变细且波动较大,有机质呈增加趋势且以海源为主,主要受东亚冬季风减弱的影响,海源有机质含量增加,与黄海暖流影响增强有关;(3)3.9~0 ka BP,沉积物粒度最细且相对稳定,有机质含量继续增加,直至1.9 ka BP趋于稳定,主要受现代环流系统和东亚冬季风影响。结果表明,南黄海粒度和整体有机质指标变化过程复杂,显示中全新世以来南黄海中部泥质区沉积环境演化的复杂性。本研究获得了南黄海高分辨率的沉积环境演化记录,不仅为沉积机制研究提供更多数据支撑,还可为区域古气候和古海洋演化提供关键的指示证据。The sedimentary environment of the South Yellow Sea(SYS)is complex under the interaction of sea and land.It has always been the focus and difficulty for sedimentary mechanism researches.In this study,multi-index records,including 196 samples of grain size and bulk organic matter indexes(TOC,TN,TOC/TN,andδ13Corg)of a gravity Core Z1 from the central South Yellow Sea mud area were obtained.Five layers of AMS14C age were determined and the highest resolution was 11 a/cm.Our results reveal that the sedimentary processes of central SYS since 6.1 ka BP could be generally divided into three stages:(1)During 6.1–5.2 ka BP,the sediments had the coarsest mean grain size and were mainly residual sand and terrestrial coarse-grained matters,the content of organic matter was very low and primarily terrigenous materials.The variation of mean grain size and organic matter content were both influenced by strong East Asian Monsoon.The low preservation efficiency of organic matter in turbulent marine environment and the remarkable dilution effect of large quantity of terrestrial input were other reasons for lower organic content.(2)During 5.2–3.9 ka BP,the sediment mean grain size was thinner with fluctuating amplitude,the organic matter was increasing and mainly marine materials.They were concerned with weakening East Asian Winter Monsoon.The increase of marine organic matter was related to the increasing influence of Yellow Sea Warm Current.(3)Since 3.9 ka BP,the mean grain size of the sediments was the smallest and relatively constant,the organic matter content was continuously increased to 1.9 ka BP,and then stabilize.They were chiefly controlled by the modern circulation system and East Asian Winter Monsoon.The mean grain size and the overall organic matter indexes explain the complexity of sedimentary environment evolution of the central South Yellow Sea mud area.High-resolution records of sedimentary environment evolution obtained in this study could provide data for sedimentary mechanism researches,moreover,which have

关 键 词：古海洋 黄海暖流 黄海冷水团 粒度 有机质 

分 类 号：P736.22[天文地球—海洋地质]