长江三角洲北翼ZKA01钻孔第四纪晚期以来的沉积环境演化  

Evolution of sedimentary environment at the ZKA01 borehole in the north wing of the Yangtze River Delta since late Quaternary

作　　者：刘宪光 杨晋炜 蒋仁[3] 梁飞刚 夏斌 王钜 胡利 孙丰瑞 董军林 LIU Xianguang;YANG Jinwei;JIANG Ren;LIANG Feigang;XIA Bin;WANG Ju;HU Li;SUN Fengrui;DONG Junlin(Institute of Geochemical Exploration and Marine Geological Surrey,East China Mineral Exploration and Development Bureau for Nonferrous Metals,Nanjing 210007,Jiangsu,China;Key Laboratory of Coastal Salt Marsh Ecosystems and Resources,Ministry of Natural Resources,Nanjing 210007,Jiangsu,China;Nanjing Center,China Geological Survey,Nanjing 210016,Jiangsu,China;Central South Geological Survey Institute of China Metellurgical Geology Bureau,Wuhan 430300,Hubei,China)

机构地区：[1]江苏省有色金属华东地质勘查局地球化学勘查与海洋地质调查研究院,江苏南京210007 [2]自然资源部滨海盐沼湿地生态与资源重点实验室,江苏南京210007 [3]中国地质调查局南京地质调查中心,江苏南京210016 [4]中国冶金地质总局中南地质调查院,湖北武汉430300

出　　处：《地质力学学报》2023年第6期856-868,共13页Journal of Geomechanics

基　　金：中国地质调查局地质调查项目(1212011220539,DD20230002)。

摘　　要：第四纪晚期以来的年代地层框架及海侵问题一直以来都是长江三角洲地区的研究热点。由于长江三角洲地区河道往复摆动、河流下切侵蚀导致地层频繁缺失,目前尚未在该地区同一个钻孔内发现完整的海侵记录。基于长江三角洲北翼东台地区ZKA01钻孔岩石地层、生物地层、古地磁年代学和光释光(OSL)测年研究,对比区域钻孔资料确定了该孔第四纪以来的地层年代框架,发现ZKA01钻孔完整地记录了晚更新世以来长江三角洲地区的5次海侵事件。结果表明,ZKA01孔B/M界线位置在108.00m处,M/G界线位置为300.25 m处。中、上更新统界线位于第Ⅲ海相层底部,即92.95m处。上更新统与全新统界线置于该钻孔发现的第Ⅰ海相层底部,即16.65m处。晚更新世以来,前3次海侵发生在MIS5(128~74 ka)阶段,其中MIS5.1海侵规模较大,仅次于全新世时期的海侵规模。第4次海侵发生在MIS3阶段(60~24 ka),在深度上和年代上相当于MIS3时期的“第Ⅱ海相层”。第5次海侵发生在MIS1(12 ka至今)阶段,沉积环境为滨岸浅水的浅海环境,该次海侵规模最大。同时发现MIS5阶段初次海侵记录在该地区各钻孔埋深大致相当,该界面可作为长江三角地区的地层划分与对比研究的标志性地层。以上研究成果对于长江三角洲地区第四纪晚期地层划分对比、沉积环境研究分析具有极其重要意义。The late Quaternary chronostratigraphic framework and marine transgression have long been research focal points in the Yangtze River Delta.The frequent channel oscillation and river incision in the Yangtze Delta have led to the frequent absence of complete stratigraphic records.Complete marine transgression records have yet to be discovered within the same borehole in this region.Based on lithostratigraphy,biostratigraphy,paleomagnetic chronology,and OSL dating studies of the ZKA01 borehole in the Dongtai area of the northern wing of the Yangtze River Delta region,the stratigraphic chronology framework since Marine Isotope Stage 5(MIS5)was established.The ZKA01 borehole was found to have comprehensively recorded five marine transgression events in the Yangtze Delta region since late Pleistocene.The results indicate that the B/M boundary of the ZKA01 borehole is located at 108 m,and the M/G boundary is at 300.25 m.The boundary between the Middle and Upper Pleistocene is positioned at the bottom of the third marine transgression layer,precisely at 92.95 m.The boundary between the Upper Pleistocene and Holocene boundaries is located at the bottom of the first marine transgression layer discovered in the borehole,precisely at 16.65 m.The first three transgressions occurred during MIS5(128–74 ka),of which MIS 5.1 had a larger scale,second only to the scale of the transgressions during the Holocene.The fourth transgression occurred during MIS3(60–24 ka),equivalent in depth and age to the"II marine phase layer"of MIS3.The fifth transgression occurred during MIS1(12 ka to present),depositing in a nearshore shallow marine environment,with the largest scale observed.Additionally,it was identified that the first transgression layer(MIS5)is approximately equivalent in burial depth across various regional boreholes,serving as a distinctive stratigraphic marker for stratigraphic division and comparative studies in the Yangtze River Delta.These research findings hold significant importance for Quaternary stratigraphic divis

关 键 词：长江三角洲 年代学 地层 沉积环境 微体生物化石 MIS5 海侵 

分 类 号：P534.63[天文地球—第四纪地质学]