基于钻孔记录探究古云梦泽沉积面貌  

Exploring sedimentary features of paleo-Yunmeng Lakes based on borehole records

作　　者：管硕 顾延生[3,4,5] 姚仕明[1,2] 丁兵[1,2] 曾玉红[6] GUAN Shuo;GU Yansheng;YAO Shiming;DING Bing;ZENG Yuhong(Key Laboratory of River and Lake Regulation and Flood Control in the Middle and Lower Reaches of the Yangtze River of Ministry of Water Resources,Changjiang River Scientific Research Institute,Wuhan 430010,China;River Research Department,Changjiang River Scientific Research Institute,Wuhan 430010,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430074,China;Hubei Key Laboratory of Wetland Evolution and Eco-Restoration,China University of Geosciences,Wuhan 430078,China;Key Laboratory of Environment and Culture in Yangtze Regions,China University of Geosciences,Wuhan 430078,China;State Key Laboratory of Water Resources Engineering and Management,Wuhan University,Wuhan 430072,China)

机构地区：[1]长江科学院水利部长江中下游河湖治理与防洪重点实验室,湖北武汉430010 [2]长江科学院河流研究所,湖北武汉430010 [3]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430074 [4]中国地质大学湿地演化与生态恢复湖北省重点实验室,湖北武汉430078 [5]中国地质大学流域环境与长江文化重点实验室,湖北武汉430078 [6]武汉大学水资源工程与调度全国重点实验室,湖北武汉430072

出　　处：《人民长江》2024年第11期30-37,共8页Yangtze River

基　　金：中央级公益性科研院所基本科研业务费专项资金项目(CKSF2024986/HL);国家自然科学基金重点项目(U23A2023)。

摘　　要：古云梦泽是晚全新世时期江汉平原与长江最主要的水沙交换载体,其形成演化特征为沉积物所记录,蕴藏了丰富的古环境、古气候信息。为了探讨古云梦泽沉积演化的规律和模式,基于2014~2019年江汉平原野外钻孔采样数据,对江汉平原钻孔沉积物的理化指标包括粒度、总有机碳、磁化率等进行分析,结合加速器质谱碳十四(AMS^(14)C)精准测年和粒度频率曲线得到晚全新世时期江汉平原整体的沉积环境变化序列,进而探讨古云梦泽沉积演化的规律和模式。结果表明:根据钻孔沉积相记录,古云梦泽形成演化过程中出现了“河流-湖泊-三角洲”复合沉积模式;钻孔横向对比发现,三角洲相沉积最先形成于江汉平原西部,并逐渐向东部扩展,表明这种复合沉积模式不仅仅只影响单个钻孔的沉积序列,还在空间上调控了整个古云梦泽的演化。研究成果揭示了历史时期全球变化背景下江汉平原河湖系统自然演变的特征与规律,对于指导江汉湖群的生态恢复和预测未来长江中下游地区江湖关系演变趋势具有重要的意义。The paleo-Yunmeng Lakes served as the primary carriers of water and sediment exchange between the Jianghan Plain and the Changjiang River during the Late Holocene.Their formation and evolution were recorded in the sediments,which contained abundant information about the paleoenvironment and paleoclimate.To explore the patterns and mechanisms of sedimentary evolution of the paleo-Yunmeng Lakes,we analyzed physical and chemical indexes,including grain size,total organic carbon,and magnetic susceptibility of borehole sediments collected from the Jianghan Plain from 2014 to 2019.By combining these analyses with Accelerator Mass Spectrometry radiocarbon dating(AMS 14 C)for accurate dating and grain size frequency curves,the overall sedimentary environment features of the Jianghan Plain during the Late Holocene were obtained.These features enabled an exploration of the patterns and modes of sedimentary evolution within the paleo-Yunmeng Lakes.The results indicated that,according to the boreholes sedimentary facies records,a"river-lake-delta"complex depositional model emerged during the formation and evolution of the paleo-Yunmeng Lakes.A horizontal comparison of the boreholes revealed that deltaic facies deposits first formed in the western part of the Jianghan Plain and gradually expanded eastward,suggesting that this complex depositional model not only influenced the sedimentary sequence of individual boreholes but also spatially regulated the evolution of the entire paleo-Yunmeng Lakes.The research results have revealed the characteristics and laws of natural evolution of river and lake systems in the Jianghan Plain under global changes in historical periods,which has important reference significance for guiding the ecological restoration of the Jianghan Lake Group,and predicting the future trend of river-lake relationship evolution in the middle and lower reaches of the Changjiang River.

关 键 词：古云梦泽演化 粒度分析 钻孔沉积物 “河流-湖泊-三角洲”复合沉积模式 江汉平原 晚全新世 

分 类 号：P532[天文地球—古生物学与地层学] P512.2[天文地球—地质学]