地学前缘 ›› 2022, Vol. 29 ›› Issue (4): 211-220.DOI: 10.13745/j.esf.sf.2022.1.18

• 深海沉积与快速气候变化 • 上一篇    下一篇

泰国湾表层沉积物陆源碎屑的粒度特征及其展现的沉积动力环境

冯铄1, 刘志飞1,*(), Penjai SOMPONGCHAIYAKUL2, 林宝治1, Martin G. WIESNER3   

  1. 1.同济大学 海洋地质国家重点实验室, 上海 200092
    2. Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
    3. Institute of Geology, University of Hamburg, Hamburg 20146, Germany
  • 收稿日期:2021-09-27 修回日期:2021-12-18 出版日期:2022-07-25 发布日期:2022-07-28
  • 通讯作者: 刘志飞
  • 作者简介:冯 铄(1997—),女,硕士研究生,海洋科学专业。
  • 基金资助:
    国家重点研发计划战略性国际科技创新合作重点专项课题(2018YFE0202402);上海市“科技创新行动计划”国际科技合作项目(20590780200)

Grain size characteristics of terrigenous clastics in surface sediments of the Gulf of Thailand and their significance for sedimentary dynamic environment

FENG Shuo1, LIU Zhifei1,*(), Penjai SOMPONGCHAIYAKUL2, LIN Baozhi1, Martin G. WIESNER3   

  1. 1. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China
    2. Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
    3. Institute of Geology, University of Hamburg, Hamburg 20146, Germany
  • Received:2021-09-27 Revised:2021-12-18 Online:2022-07-25 Published:2022-07-28
  • Contact: LIU Zhifei

摘要:

海洋碎屑沉积物的粒度特征是海底沉积动力环境的直接体现,是用来研究海洋动力环境变化的重要手段,尤其是陆架海底表层沉积物的粒度分布,对于研究沿岸和水柱底边界层现今海洋动力环境可起到重要作用。该项研究通过调查遍布泰国湾至湄公河口海底表层沉积物陆源碎屑的粒度分布特征,以期获得影响现今特定海域沉积作用的海洋动力环境过程。粒度分析的结果显示,泰国湾表层沉积物的陆源碎屑以细砂-细粉砂为主,分选总体较差,频率分布以正偏为主。其中,细砂-极细砂组分主要分布在曼谷湾和柬埔寨沿岸。湄公河岸外沉积物为细砂,且分选比泰国湾区域的沉积物要好。这些表层沉积物的粒度特征具有良好的环境变化指示作用。湄公河岸外分选较好、近于正态分布的中砂沉积物指示了波浪作用下的沉积环境。曼谷湾和柬埔寨沿岸分选较差的中砂-细砂粗粒沉积物反映了潮汐和波浪的共同作用;泰国湾东西沿岸区域分选中等、呈正偏态的极细砂-中粉砂沉积物体现了潮汐的控制作用;而泰国湾中部分选较差的沉积物则指示了表层洋流作用。研究表明,泰国湾和湄公河岸外表层沉积物陆源碎屑的粒度分布特征可用于区分不同海洋动力因素的控制作用,揭示出泰国湾的沉积动力环境主要受潮汐、波浪和洋流的共同影响,湄公河岸外的沉积动力环境主要受波浪的影响。

关键词: 粒度, 表层沉积物, 沉积动力环境, 泰国湾

Abstract:

The grain size characteristics of marine clastic sediments can directly reflect the marine sedimentary dynamic environment, thus can be used to study the variation of marine dynamic environment. In particular, the grain size distribution of surface sediments on the continental shelf plays an important role in studying the modern marine dynamic environment of coastal and water column bottom boundary layer. This research investigated the grain size distribution characteristics of terrigenous clastics in surface sediments collected from the Gulf of Thailand and the Mekong River estuary, to obtain the marine dynamic environmental processes affecting the particle sedimentation in specific sea areas. The results of grain size analysis show that the terrigenous clastics in surface sediments in the Gulf of Thailand are composed mainly of poorly sorted fine sand to fine silt, characterized mostly by positive skewness in frequency distribution patterns. The fine to very fine sand components are mainly distributed at the bay of Bangkok and shelves off Cambodia. The sediments off the Mekong River are fine sand and the sorting is better than that in the Gulf of Thailand. These grain size characteristics of surface sediments can serve as good proxies to explicitly indicate the environmental variations in this area. The well sorted medium sand with nearly normal distribution patterns in sediments off the Mekong River indicate the depositional environment under the influence of the waves. The poorly sorted medium sand to fine sand sediments in the bay of Bangkok and off Cambodia reflect the combined effect of tides and waves. The very fine sand to medium silt sediments with medium sorting and positive skewness in the east and west coast of the Gulf of Thailand reflect the controlling effect of tides. And the sediments in the central Gulf of Thailand with poorly sorting indicate the influence of surface currents. This study shows that the grain size distribution characteristics of terrigenous clastics in surface sediments of the Gulf of Thailand and off the Mekong River can be used to distinguish the control effects of different marine dynamic factors, and to reveal that the sedimentary dynamic environment in the Gulf of Thailand is mainly affected by tides, waves and currents and the sedimentary dynamic environment off the Mekong River is affected by waves.

Key words: grain size, surface sediments, sedimentary dynamic environment, Gulf of Thailand

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