南沙群岛礼乐滩周边海域表层沉积硅藻分布特征  

DISTRIBUTION CHARACTERISTICS OF DIATOMS IN THE SURFACE SEDIMENT AROUND THE LIYUE BANK,NANSHA ISLANDS,SOUTH CHINA SEA

作　　者：李顺[1,2] 荆夏 蔡观强[1,2] 张江勇 李波[1,2] 赵利 LI Shun;JING Xia;CAI Guanqiang;ZHANG Jiangyong;LI Bo;ZHAO Li(Guangzhou Marine Geological Survey,Ministry of Natural Resources,Guangzhou 510075,China;Key Laboratory of Marine Mineral Resources,Ministry of Natural Resources,Guangzhou 510075,China)

机构地区：[1]自然资源部广州海洋地质调查局,广州510075 [2]自然资源部海底矿产资源重点实验室,广州510075

出　　处：《微体古生物学报》2020年第1期59-67,共9页Acta Micropalaeontologica Sinica

基　　金：中国地质调查局地质调查项目(DD20190627,DD20190209,DD20160138,DD20190378,GZH201400203)共同资助。

摘　　要：本文对南海礼乐滩周边海域的表层沉积物样品进行了硅藻分析,在109个样品中鉴定出硅藻45属91种及变种。所有样品中均含有极丰富的硅藻,丰度均值为313.2万粒/克,其中Thalassionema nitzschioides占绝对优势。依据典型相关分析结果,研究区可划分为4个硅藻组合区。其中区域I和II位于第一主轴负方向,指示水深相对较浅、沉积物平均粒径相对较粗、SiO2和TOC含量相对较高的沉积环境,主要分布T.nitzschioides,Thalassiosinema frauenfeldii,Cyclotella striata和Nitzschia bicapitata,Thalassionema nitzschioides var.parva,Nitzschia interruptestriata,代表受巴拉望岛物质和沿岸流影响的沉积环境。区域III和IV位于第一主轴正方向,指示水深相对较深、沉积物平均粒径相对较细、SiO2和TOC含量相对较低的沉积环境,主要分布T.frauenfeldii,T.nitzschioides,N.interruptestriata,Fragilariopsis doliolus和T.frauenfeldii,T.nitzschioides,分别代表的是南沙诸群礁周边及海槽区和深海海盆的沉积环境。In order to disclose the modern distribution of diatoms around the Liyue Bank,Nansha lslands,South China,a new data set including the relative abundance of diatom species preserved in a total of 109surface sediments was generated.91diatom species or varieties are identified,belonging to 45genera.Diatom abundance ranges from 200000to 7750000valves/g,with an average of 3132000valves/g.Thalassionema nitzschioides has the highest abundance.According to the result of canonical correlation analysis,the study area can be divided into four diatom assemblages.Assemblages I and II are located in the negative direction of the first CCA-axis,indicating the sedimentary environment with relatively shallow water depth,relatively coarser grain size,high SiO2and TOC content.The main species are T.nitzschioides,Thalassiosinema frauenfeldii,Cyclotella striata and Nitzschia bicapitata,Thalassionema nitzschioides var.parva,Nitzschia interruptestriatain AssemblageⅠandⅡ,indicating that sedimentary environment affected by Palawan island material and coastal current.Areas III and IV are located in the positive direction of the first CCA-axis,indicating the sedimentary environment with relatively deep water depth,relatively fine grain size of sediments,and low SiO2and TOC content.The main species in these area are T.frauenfeldii,T.nitzschioides,N.interruptestriata,Fragilariopsis doliolus and T.frauenfeldii,T.nitzschioides,representing the Nansha reefs,west Liyue trough and deep sea basins sedimentation environment.

关 键 词：硅藻 表层沉积 礼乐滩 南沙群岛 

分 类 号：Q914[天文地球—古生物学与地层学]