印度洋东经90°海岭现代沉积物稀土元素组成及其物源示踪意义  

Rare earth element composition of the surface sediments from the Ninetyeast Ridge and its implications for provenance

作　　者：齐文菁 李小艳 范德江[1,3] 张辉 殷征欣 刘升发 QI Wenjing;LI Xiaoyan;FAN Dejiang;ZHANG Hui;YIN Zhengxin;LIU Shengfa(College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;Key Laboratory of Marine Geology and Metallogeny,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,China;South China Sea Marine Engineering Surveying Center,State Oceanic Administration,Guangzhou 510275,China)

机构地区：[1]中国海洋大学海洋地球科学学院,青岛266100 [2]自然资源部第一海洋研究所,自然资源部海洋地质与成矿作用重点实验室,青岛266061 [3]青岛海洋科学与技术试点国家实验室海洋地质过程与环境功能实验室,青岛266237 [4]国家海洋局南海调查技术中心,广州510275

出　　处：《海洋地质与第四纪地质》2022年第2期92-100,共9页Marine Geology & Quaternary Geology

基　　金：全球变化与海气相互作用专项“东印度洋IND-CJ04区块海底底质和底栖生物调查”(GASI-02-IND-CJ04)。

摘　　要：基于印度洋东经90°海岭42个表层沉积物的粒度和稀土元素(REE)组成及其空间分布特征,判别了研究区现代沉积物的主要来源,并结合水动力格局等要素探讨了东经90°海岭北部区域沉积物输运方式。结果显示,研究区42个表层沉积物总稀土含量(∑REE)为26.37~156.8μg/g,平均值为57.35μg/g,特点是轻稀土含量(∑LREE)高,重稀土含量(∑HREE)低且均一、存在明显的Ce和Eu异常。REE组成和空间分布受沉积物来源控制显著,球粒陨石标准化后的Sm/Nd-δEu物源判别图以及判别函数(FD)结果显示,研究区北部表层沉积物的最主要来源是伊洛瓦底江陆源物质,次要来源是戈达瓦里-克里希纳河输入的印度半岛物质,而南部区域则受苏门答腊岛陆源物质影响显著。不同源区沉积物在研究区的输运过程主要受控于热带季风系统驱动下的季节性表层环流以及浊流和风。Spatial distribution patterns of grain size and rare earth elements(REE)are studied in this paper for the 42 surface sediment samples collected from the Ninetyeast Ridge of the Indian Ocean.The main sources of sediments are identified and the sediment transport modes are discussed on the hydrodynamic environment features.The results suggest that the total concentrations of rare earth elements in the 42 surface sediments of the study area vary between 26.37μg/g and 156.8μg/g,with an average at 57.35μg/g.The samples are rich in light REE and uniform in heavy REE with obvious negative anomalies of Eu and Ce.The composition and spatial distribution of REE are significantly controlled by the source of sediments.According to the chondrite-normalized Sm/Nd-δEu diagram for provenance identification and the discriminant function(FD),the sediments in the northern study area are mainly coming from the Irrawaddy River,and the subordinate is sourced from the Indian Peninsula by the Godavari River-Krishna River.The sediments in the southern study area are significantly affected by the Sumatra.The transportation process of sediments from different sources in the study area is mainly controlled by seasonal surface circulation driven by the tropical monsoon system,turbidity currents and wind.

关 键 词：沉积物 稀土元素 物源 东经90°海岭 印度洋 

分 类 号：P736.4[天文地球—海洋地质]