欢迎访问《高校地质学报》官方网站,今天是
分享到:

高校地质学报 ›› 2022, Vol. 28 ›› Issue (1): 129-139.DOI: 10.16108/j.issn1006-7493.2020035

• 其他学科 • 上一篇    

杭州湾北岸更新世以来沉积环境记录及古气候变迁

林钟扬1,3,刘 健1,金翔龙2,4*,吴 鸣1,赵旭东1,潘少军1   

  1. 1. 浙江省地质调查院,杭州 311203;
    2. 自然资源部第二海洋研究所 自然资源部海底科学重点实验室,杭州 310012;
    3. 自然资源部 平原区农用地生态评价与修复工程技术创新中心,杭州 311203;
    4. 中国地质大学 海洋学院,武汉 430074
  • 出版日期:2022-02-20 发布日期:2022-02-20

A Sedimentary Record of Environmental and Paleoclimatic Changes in the North Shore of Hangzhou Bay since the Pleistocene

LIN Zhongyang1, 3,LIU Jian1,JIN Xianglong2, 4*,WU Ming1,ZHAO Xudong1,PAN Shaojun1   

  1. 1. Zhejiang Institute of Geological Survey, Hangzhou 311203, China;
    2. Key Laboratory of Submarine Geosciences, Second Institude of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China;
    3. Technical innovation center of agricultural land ecological evaluation and restoration project in plain area,
    Ministry of Natural Resources, Hangzhou 311203, China;
    4. College of Marine Science and Technology, China University of Geosciences, Wuhan 430074, China
  • Online:2022-02-20 Published:2022-02-20

摘要: 文章通过对杭州湾北岸孔深为237.80 m的BZK04钻孔进行沉积物岩性、微体古生物、孢粉组合、粒度含量、古地磁和OSL测年的综合分析,讨论研究区更新世以来沉积环境演变及古气候变迁特征,建立第四纪多重地层划分对比框架。结果显示, BZK04孔岩心自下而上可分为基岩长河组碳质泥岩(Ech)和早更新世以来的嘉兴组(N-Qp1 j)、前港组(Qp2q)、东浦组(Qp3d)、宁波组(Qp3n)、镇海组(Qhzh)地层;有孔虫鉴定为11属17种,其中包括16种底栖有孔虫,1种浮游有孔虫;介形类鉴定为8属8种;孢粉分析显示含37种类型,其中木本植物花粉18种,草本植物花粉11种,蕨类孢子8种,孢粉组合中木本植物含量最高,约为85.1%,蕨类孢子次之,约为8.7%,草本植物花粉含量仅为6.3%。根据岩性分层特征、沉积相、孢粉、有孔虫及介形虫以及粒度分布频率曲线对钻孔的沉积环境进行综合分析,可将沉积环境记录划分18个孢粉组合带和七个古气候旋回变迁,其中早更新世为河流相和河湖相沉积,揭示第三暖期—第4冷期的两个古气候旋回;中更新世以河流相、湖泊相和河湖相为主,揭示第五暖期—第6冷期的两个古气候旋回;晚更新世以潮坪相、河口湾相、浅海相沉积为主,对应第七暖期—第8冷期的两个古气候旋回;全新世时期为潮坪相和河湖相沉积,对应大西洋期和亚北方期。研究结果为进一步掌握长江三角洲南翼更新世以来的第四纪沉积环境变化、地层划分和古气候演变等提供基础资料。

关键词: 杭州湾北岸, 第四纪, 孢粉, 沉积环境, 古气候

Abstract: The BZK04 borehole (237.80 m deep) is located in the south wing of the Yangtze River Delta and the north bank of Hangzhou Bay. The core contains a relatively complete and continuous sedimentary sequence since the Pleistocene. In this study, the sediment lithology, micropaleontology, sporopollen assemblage, particle size content, paleomagnetism and OSL dating of the core were analyzed comprehensively, the characteristics of depositional environment evolution and paleoclimatology changes since the Pleistocene in the research area were discussed, and the framework of quaternary multiple stratigraphic divisions and correlatiosn was established. The results show that from bottom to top, the BZK04 core can be divided into carbonaceous mudstone (Ech) of the Changhe Formation, and the Jiaxing Formation(N-Qp1j), Qiangang Formation( Qp2q), Dongpu Formation( Qp3d), Ningbo Formation (Qp3n) and Zhenhai Formation (Qhzh) since the early Pleistocene epoch; Foraminifera of 17 species in 11 genera were identified , including 16 benthonic foraminifera and 1 planktonic foraminifera; The ostracod of 8 species in 8 genera was identified ; Pollen analysis reveals that there were 37 types of pollen, including 18 woody plant pollen, 11 herbaceous pollen, and 8 fern spore; The content of woody plants was the highest in the palynological assemblage (85.1%), followed by fern spores (8.7%) and herb pollen (6.3%). According to the comprehensive analysis of the sedimentary environment of borehole by lithologic stratification features, sedimentary facies, sporopollen, foraminifera and ostracodes, and grain size distribution frequency curve, the depositional environmental record is characterized by 18 pollen assemblages and 7 paleoclimatic cyclic changes, among which the early Pleistocene is dominated by fluvial and lacustrine facies deposits, indicating two paleoclimatic cycles from the third warm period to the fourth cold period; The middle Pleistocene was dominated by fluvial facies, lacustrine facies, and fluvial and lacustrine facies, revealing two paleoclimatic cycles from the fifth warm period to the sixth cold period; The late Pleistocene is dominated by the tidal-flat facies, estuarine facies and neritic facies, corresponding to two paleoclimatic cycles from the seventh warm period to the eighth cold period; In the Holocene, there were tidal-flat facies, fluvial and lacustrine facies, corresponding to the Atlantic and boreal periods. This study provides an important basis for further understanding the changes in quaternary sedimentary environment, the stratigraphic divisions and the paleoclimate evolution since the Pleistocene in the southern side of the Yangtze River Delta.

Key words: north shore of Hangzhou Bay, Quaternary, sporopollen, sedimentary environment, paleoclimate

中图分类号: