蔡观强, 李顺, 赵利, 高红芳, 钟和贤. 南海海盆中部表层沉积物地球化学特征[J]. 海洋地质与第四纪地质, 2018, 38(5): 90-101. DOI: 10.16562/j.cnki.0256-1492.2018.05.009
引用本文: 蔡观强, 李顺, 赵利, 高红芳, 钟和贤. 南海海盆中部表层沉积物地球化学特征[J]. 海洋地质与第四纪地质, 2018, 38(5): 90-101. DOI: 10.16562/j.cnki.0256-1492.2018.05.009
CAI Guanqiang, LI Shun, ZHAO Li, GAO Hongfang, ZHONG Hexian. Geochemical characteristics of surface sediments from the middle deep-sea basin of South China Sea[J]. Marine Geology & Quaternary Geology, 2018, 38(5): 90-101. DOI: 10.16562/j.cnki.0256-1492.2018.05.009
Citation: CAI Guanqiang, LI Shun, ZHAO Li, GAO Hongfang, ZHONG Hexian. Geochemical characteristics of surface sediments from the middle deep-sea basin of South China Sea[J]. Marine Geology & Quaternary Geology, 2018, 38(5): 90-101. DOI: 10.16562/j.cnki.0256-1492.2018.05.009

南海海盆中部表层沉积物地球化学特征

Geochemical characteristics of surface sediments from the middle deep-sea basin of South China Sea

  • 摘要: 分析了南海海盆中部224个站位表层沉积物的常量组分和微量元素组成,结果表明,这些沉积物与大陆上地壳相比,具有相对贫Si和富Fe、Mg、Na、Ca、Mn的特点,微量元素含量总体与大陆上地壳较为相近。表层沉积物化学组分可以划分为4类组合:硅酸盐碎屑组分、钙质生物碎屑组分、火山碎屑组分和自生矿物组分;硅酸盐碎屑组分和钙质生物碎屑组分占绝对优势,两者含量互为消长,自生矿物和火山碎屑含量较低,仅在局部区域起到相对明显的贡献。南海海盆中部表层沉积物化学组成主要受水深、沉积作用和物质来源3个因素控制;水深和底流搬运作用影响钙质生物碎屑分布,深水海盆碳酸盐溶解作用强烈,海盆中部沉积物钙质生物碎屑含量低,而底流作用则将陆坡区钙质碎屑搬运至海盆边缘区域。沉积物地球化学特征指示,海盆中部沉积物陆源碎屑物质主要来自于西部或西南部,火山碎屑物质可能主要来自于吕宋岛弧火山喷发,并堆积于扩张中心以北和海盆东部区域。

     

    Abstract: This paper presents the major and trace elements compositions of the 224 surface sediments taking from the middle deep-sea basin of South China Sea (SCS). Data shows that the samples have low SiO2 and relatively high Fe2O3, MgO, CaO, Na2O, and MnO. The abundances of most trace elements are also higher compared to the upper continental crust. The sediments are composed of four fractions, i.e. the terrigenous silicate fraction, calcareous clastic fraction, pyroclastic fraction and authigenic mineral fraction. The terrigenous silicate and calcareous clastic fractions dominate, while the pyroclastic and authigenic mineral fractions are relatively low in general but significant in some regions. The geochemical characteristics of the surface sediments in the middle deep-sea basin of SCS are mainly controlled by water depth, depositional processes, and sediment sources. The distribution of calcareous clastic fraction is mainly controlled by water depth and deep bottom current transportation. The intensive dissolution of calcium carbonate results in the relatively low content of calcareous clastic fraction in the deep-sea basin deposits, while the terrigenous sediments are supplied to the middle deep-sea basin mainly from the source regions to the west and southwest. The pyroclastic fraction, which is characterized by relatively high content of Na2O, is possibly derived from the Luzon arc, and mainly deposited in the eastern deep-sea basin and the region to the north of the spreading ridge.

     

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