中国地质调查2025，Vol.12Issue(6)：49-60,12.DOI:10.19388/j.zgdzdc.2024.184
杭州湾北岸第四纪沉积特征与古气候演化
Quaternary sedimentary characteristics and paleoclimate evolution on the northern coast of Hangzhou Bay
摘要
Abstract
The northern coast of Hangzhou Bay is distributed with extensive and thick Quaternary strata,and con-ducting research on these strata can help infer the Quaternary paleoclimate evolutionary characteristics.Based on the data of BZK05 borehole core,the authors in this research established a framework for multi-layered Quater-nary stratigraphic correlation and discussed the sedimentary environment and paleoclimate evolution since the Pleistocene,based on the analysis results of grain size,14C dating,optically stimulated luminescence dating,pal-eomagnetism,pollen assemblage,microfossil species identification and abundance statistics,and comprehensive logging.The lithological analysis revealed that a small amount of Early Cretaceous Jinhua Formation mudstone was exposed at the base of BZK05 borehole.The Pleistocene strata of this borehole were divided into five formations from bottom to top through multi-layered stratigraphic correlation,and the depth of 35.9 m in BZK05 borehole marked the boundary between Pleistocene and Holocene strata.The grain size analysis showed that the 0～80 m section exhibited fine-grained unimodal distribution,reflecting a stable sedimentary environment primarily domi-nated by marine and lacustrine deposits.The 81～150 m section displayed chaotic grain size frequency curves,indicating complex and diverse sedimentary processes.The 151～225 m section showed a strong coarse-grained peak,suggesting sedimentation dominated by alluvial(proluvial)processes,indicating a riverine depositional en-vironment.The 119～232 m section exhibited low and concentral paleomagnetic magnetic susceptibility values,indicating that the sedimentary sources of the lower part of this borehole were generally stable and similar.A total of 115 pollen species were identified,predominantly from woody and herbaceous plant pollen,and 11 pollen zones were delineated based on pollen abundance characteristics.fifteen genera and twenty three species of foraminifera were identified,and most of them were benthic foraminifera,and six stratigraphic intervals were divided.six gen-era and seven species of Ostracods were identified,which could be classified into three stratigraphic intervals.Based on multiple stratigraphic characteristics such as lithology,logging curves,and microfossil distribution,and combined with comprehensive analysis of sedimentary environment and paleoclimate evolution,the paleoclimate environment recorded in this borehole could be divided into nine warm intervals and six cold intervals.The re-search findings could provide guiding significance for deepening the Quaternary stratigraphic division,identifica-tion of sedimentary environments,and understanding paleoclimatic evolution processes in Yangtze River delta re-gion.关键词
第四纪/沉积层序/多重地层划分/古气候/杭州湾北岸Key words
Quaternary/sedimentary sequence/multiple stratigraphic divisions/Paleoclimate/the northern coast of Hangzhou Bay分类
天文与地球科学引用本文复制引用
潘少军,张建芳,顾明光,赵旭东,林钟扬,蔡晓亮..杭州湾北岸第四纪沉积特征与古气候演化[J].中国地质调查,2025,12(6):49-60,12.基金项目
浙江省科技厅"尖兵""领雁"研发攻关计划项目(编号:2022C03141)及中国地质调查局"浙江1∶5万嘉兴市、平湖市、嘉善县、盛泽镇、新丰镇幅区域地质调查(编号:1212011220538)"联合资助. （编号:2022C03141）
