杭嘉湖平原ZK3钻孔沉积物粒度端元分析及其气候-海平面响应  

Grain size end-member analysis in sediments from ZK3 borehole and its responses to climate-sea level in Hang jiahu Plain,China

作　　者：江志霖 毛龙江 王婷 邹春辉 赵成双苹 刘斌[4] 王宁远[4] 陈明辉[4] 莫多闻[3] JIANG Zhilin;MAO Long jiang;WANG Ting;ZOU Chunhui;ZHAO Chengshuangping;LIU Bin;WANG Ningyuan;CHEN Minghui;MO Duowen(Institute of Science and Technology History and Meteorological Civilization,Nanjing University of Information Science and Technology,Nanjing 210044,China;School of Marine Sciences,Nanjing University of Information Science and Technology,Nanjing 210044,China;College of Urban and Environmental Sciences,Peking University,Beijing 100871,China;Zhejiang Provincial Institute of Archaeology and Cultural Relics,Hangzhou 310014,China)

机构地区：[1]南京信息工程大学科技史与气象文明研究院,南京210044 [2]南京信息工程大学海洋科学学院,南京210044 [3]北京大学城市与环境学院,北京100871 [4]浙江省文物考古研究所,杭州310014

出　　处：《地球环境学报》2024年第2期306-316,341,共12页Journal of Earth Environment

基　　金：浙江省文物考古研究所委托项目(2021h629);国家社会科学基金项目(19ZDA231);国家重点研发计划(2020YFC1521605)。

摘　　要：杭嘉湖平原位于海陆交互的长江三角洲地区,极易受到海平面升降和极端气候事件的影响,对全球环境变化十分敏感。应用非参数化粒度端元分析模型提取杭嘉湖平原ZK3岩芯沉积物的端元组分,分析其物质来源;并结合植物藻类和磁化率指标全面揭示各端元组分对区域全新世气候-海平面变化响应。结果表明:(1)EM1(16.4 μm)主要为洪泛沉积物,EM2(35.3 μm)主要为湖相沉积物,EM3(58.9 μm)则为海相沉积物;(2)杭嘉湖平原8000 a BP以来的气候-海平面变化大致可分为四个阶段:约8000—6200 a BP,受东亚夏季风影响,气候温暖湿润,海平面上升并趋于稳定,区域内同时受到海洋和陆源输入影响,发育海陆过渡相沉积;约6200—4800 a BP,气候趋于干凉化,陆地面积扩大,沉积环境转变为河流为主的洪泛沉积;至4800—3100 a BP,气候回暖,海平面略有回升,发育为湖相沉积;3100—140 a BP,气候趋冷干化,海平面下降,广泛发育为泛滥平原沉积环境。Background,aim,and scope The Hang jiahu Plain,situated in the Yangtze River Delta region,experiences intense sea-land interactions.Consequently,it is highly vulnerable to fluctuations in sea levels,extreme climatic events,and global environmental changes.The grain size end-member analysis method facilitates the understanding of the relationships among various sediment sources,depositional mechanisms,and pathways,as recorded in the particle size data of the sediments.In this study,we employ a non-parametric grain size end-member analysis model to extract the end-member components of sediments from core ZK3 in the Hang jiahu Plain and analyze their material sources.By utilizing plant algae and magnetic susceptibility,we comprehensively reveal the response of end-member components to regional Holocene climate and sea-level changes.Materials and methods Particle size,magnetic susceptibility,plant algae,and optically stimulated luminescence(OSL)sediment samples have been analyzed using MATLAB R2022 software for non-parametric decomposition of the particle size data into end-member components.Results indicate that borehole ZK3 recorded environmental changes in the Hang jiahu Plain since 8000 a BP.The non-parametric method decomposed the particle size data into three end-members:EM1=16.4μm,EM2=35.3μm,and EM3=58.9μm.The abundances of Concentricystes and Spiniferites varied significantly with core depth,with a lower algal content between 1000—500 cm and a significant increase in the 500—0 cm range.The trends of magnetic susceptibility decreased in a fluctuating manner with depth.Discussion The sources of the three grain size end-members in the ZK3 borehole are identified as follows:EM1(16.4μm)is the finest fraction,representing flood deposits from the river.EM2(35.3μm)is the most abundant fraction,indicating lacustrine sedimentation.EM3(58.9μm)is the coarsest fraction,suggesting marine sediments associated with the high sea level in the Yangtze River Delta region during the Holocene.The climate-sea level changes

关 键 词：粒度 端元分析 物源 气候-海平面 杭嘉湖平原 

分 类 号：P512.2[天文地球—地质学] P731.23P467