孟加拉湾南部表层沉积物稀土元素组成及其物源指示意义  

Rare earth element composition of the surface sediments from the south Bay of Bengal and its implications forprovenance

作　　者：孙兴全[1,2,3] 刘升发 李景瑞 曹鹏 张辉 赵广涛 Somkiat Khokiattiwong[4] Narumol Kornkanitnan 石学法 SUN Xingquan;LIU Shengfa;LI Jingrui;CAO Peng;ZHANG Hui;ZHAO Guangtao;Somkiat Khokiattiwong;Narumol Kornkanitnan;SHI Xuefa(College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;Key Laboratory of Marine Sedimentology and Environmental Geology,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266061,China;Marine and Coastal Resources Research and Development Institute,Department of Marine and Coastal Resources,Bangkok 10210,Thailand)

机构地区：[1]中国海洋大学海洋地球科学学院,海底科学与探测技术教育部重点实验室,青岛266100 [2]自然资源部第一海洋研究所,海洋沉积与环境地质自然资源部重点实验室,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266061 [4]Marine and Coastal Resources Research and Development Institute,Department of Marine and Coastal Resources,Bangkok 10210,Thailand

出　　处：《海洋地质与第四纪地质》2020年第2期80-89,共10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-CJ03区块海底底质和底栖生物调查”(GASI-02-IND-CJ03);“全球变化与海气相互作用”专项“亚洲大陆边缘“源-汇”过程与陆海相互作用”(GASI-GEOGE-03)。

摘　　要：基于孟加拉湾南部98个表层沉积物的稀土元素组成及其空间分布特征,判别了研究区表层沉积物主要来源,并结合水动力环境等探讨了孟加拉湾南部区域沉积物输运方式。结果表明,研究区表层沉积物稀土元素总含量范围为67.62~180.67μg/g,其平均值为100.85μg/g,且具有轻稀土富集、重稀土均一、明显的Eu负异常的特征。基于稀土元素主要参数,可将研究区分为两个区域,Ι区位于研究区西部,Ⅱ区位于研究区东部。根据球粒陨石标准化后的La/Yb-Sm/Nd物源判别图解可知,研究区表层沉积物的最主要来源为恒河-布拉马普特拉河搬运的喜马拉雅山侵蚀物质,其对整个研究区均有重要影响;次要来源为戈达瓦里河-克里希纳河输送的印度半岛物质,其主要影响范围为研究区西侧的Ι区。不同源区沉积物在研究区的输运过程主要受控于季节性表层环流,其驱动力为印度季风系统。Rare earth element(REE)compositions and their spatial distribution pattern for 98 surface sediment samples collected from the southern part of the Bay of Bengal are carefully studied in this paper.The main sources of sediments are identified and the sediment transport modes discussed in combination with the hydrodynamic environment features.The results suggest that the total concentrations of rare earth elements in the surface sediments of the study area vary between 67.62μg/g and 180.67μg/g,with an average at 100.85μg/g.The samples are rich in light REE and uniform in heavy REE with an obvious negative anomaly of Eu.Based on the major parameters of REE,the study area can be subdivided into two provinces,the provinceΙlocated in the west part of the study area and the provinceⅡlocated in the east.According to the chondrite-normalized La/Yb-Sm/Nd diagram for provenance identification,most of the surface sediments of the study area is provided by the erosion of the Himalayan Mountain and transported by the Ganges-Brahmaputra River.The subordinate source is the Indian Peninsula,of which the sediments were transported by the Godavari River-Krishna River in the provinceΙlocated in the west part of the study area.The transportation of sediments in different source areas is mainly controlled by the seasonal surface circulation driven by the Indian monsoonsystem.

关 键 词：孟加拉扇 稀土元素 物质来源 季风环流 东北印度洋 

分 类 号：P736.4[天文地球—海洋地质]