古地理学报 ›› 2025, Vol. 27 ›› Issue (4): 1010-1025. doi: 10.7605/gdlxb.2025.024

• 地球化学及沉积环境 • 上一篇    下一篇

南海西北部陆架第四系沉积物粒度特征及其沉积环境指示*

葛家旺1(), 成湘1, 赵晓明1(), 刘宇明2, 李旭彪1, 张欣1   

  1. 1 西南石油大学地球科学与技术学院,四川成都 610500
    2 中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,陕西西安 710061
  • 收稿日期:2023-10-26 修回日期:2024-12-13 出版日期:2025-08-01 发布日期:2025-07-30
  • 通讯作者: 赵晓明,男,1982年生,教授,主要从事深水沉积学和开发地质学方面的教学和科研工作。E-mail: zhxim98@163.com。
  • 作者简介:

    葛家旺,男,1988年生,副研究员,主要从事定量层序地层学、沉积学及开发地质学方面的教学和科研工作。E-mail:

  • 基金资助:
    *四川省科技计划资助-自然科学基金(2023NSFSC0810); 国家自然科学基金项目(41902124)

Characteristics of grain size of the Quaternary sediments and their palaeoenvironmental implications in continental shelf of northwestern South China Sea

GE Jiawang1(), CHENG Xiang1, ZHAO Xiaoming1(), LIU Yuming2, LI Xubiao1, ZHANG Xin1   

  1. 1 School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China
    2 State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment, Chinese Academy of Sciences,Xi’an 710061,China
  • Received:2023-10-26 Revised:2024-12-13 Online:2025-08-01 Published:2025-07-30
  • Contact: ZHAO Xiaoming,born in 1982,a professor,is engaged in deep water sedimentology and oil exploitation geology teaching and research. E⁃mail: zhxim98@163.com.
  • About author:

    GE Jiawang,born in 1988,an associate researcher,is engaged in teaching and quantitative sequence stratigraphy,tectono-sedimentology and oil exploitation geology research. E-mail:

  • Supported by:
    Sichuan Science and Technology Program-Natural Science Foundation of Sichuan(2023NSFSC0810); National Natural Science Foundation of China(41902124)

摘要: 沉积物的粒度数据可反映水动力特征及陆源物质构成,综合反馈海平面升降、区域物源及气候环境变化等信息,其中粒度数据中环境敏感因子是沉积环境及季风强度的良好指标。南海西北浅水陆架地区系统的钻井资料为水动力和气候变化研究提供了良好的研究载体,本研究基于获取的陆架区第四系52件样品的粒度特征分析认为,南海西北部陆架沉积物主要由黏土和粉砂组成,自下而上粒度呈“细—粗”的变化趋势,水动力作用增强。分别采用粒级—标准偏差法、端元组分分析法和主成分因子分析法对沉积物样品提取环境敏感组分,以探讨东亚季风气候的强度变化与敏感组分的响应关系。结果表明,不同方法提取出的细粒和粗粒组分含量呈现出相同的变化趋势,说明3种方法均适用于南海西北部陆架区环境敏感组分分析。端元组分分析法获得的端元组分的比值 EM1/(EM1+EM2+EM3+EM4),与主成分因子分析法分离出的4个粒级主成分计算得出的综合指标GS,具有相同的变化趋势,可作为东亚夏季风相对强度变化的替代指标; 3种方法综合得出的4.03~8.68 μm细粒组分含量变化也可指示东亚夏季风的强度变化。中更新世气候转型(约0.8-0.9 Ma)之后,东亚季风的变化幅度加剧,夏季风有所增强,冬季风显著增强后减弱; 在0.9 Ma之后,海平面下降造成陆架暴露,粗粒沉积物随之增多。

关键词: 粒度特征, 环境敏感组分, 沉积环境, 第四系, 南海西北部陆架

Abstract:

The grain size data of sediments can quantitatively reflect hydrodynamic characteristics and terrestrial material composition,providing comprehensive insights into sea-level fluctuations,regional sources,and climate environmental changes. Among these data,environmentally sensitive factors in the particle size data serve as excellent indicators of sedimentary environment and monsoon intensity. The abundant drilling data from the northwestern shallow water shelf of the South China Sea provide an excellent research platform for studying hydrodynamics and climate change. Based on the particle size analysis of 52 Quaternary samples in the continental shelf area,it is concluded that the continental shelf sediments in the northwest of the South China Sea are primarily composed of clay and silt. From bottom to top,hydrodynamic activity gradually intensifies,resulting in a relatively turbulent overall sedimentary environment,with variations in source input and hydrodynamic activity at different times. To explore the response relationship between the East Asian monsoon intensity and the response of sensitive components,environmentally sensitive components in sediment samples were extracted using the grain-size-standard deviation method,the end-member component analysis,and the principal component factor analysis. The results show that the contents of fine and coarse grain components extracted by different methods exhibit the same trends. Therefore,it is considered that all three methods are suitable for analyzing environmental sensitive components in the northwestern shelf area of the South China Sea. The ratio of EM1/(EM1+EM2+EM3+EM4)obtained by end-member component analysis and the comprehensive index GS calculated from the four particle size main components separated by principal component factor analysis show the same trend and it thus can be used as alternative indicators of the relative intensity of the East Asian winter and summer monsoons. The content variation of 4.03~8.68 μm fine fractions obtained by the three methods can also indicate the intensity variation of the East Asian summer monsoon. After the climate transition in the Mid-Pleistocene Climate Transition(around 0.8-0.9 Ma),the amplitude of East Asian monsoon variations intensified,with a significant strengthening of the winter monsoon. After 0.9 Ma,the shelf is exposed as a result of sea level fall,with a subsequent increase in coarse-grained sediments.

Key words: grain size characteristics, environmentally sensitive components, sedimentary environment, Quaternary, shelf of northwestern South China Sea

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