孟加拉湾中部沉积物地球化学特征及其古海洋学意义  

Geochemical characteristics of sediments in the central Bay of Bengal and their significances for paleoceanography

作　　者：谭龙 刘建国[2,3] 黄云 Md Hafijur Rahaman Khan 徐政 刘升发 石学法 TAN Long;LIU Jian-guo;HUANG Yun;Md Hafijur Rahaman Khan;XU Zheng;LIU Sheng-fa;SHI Xue-fa(University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China;Laboratory for Marine Geology,Pilot Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266237,China;College of Marine Sciences,Hainan University,Haikou570228,China;Key Laboratory of Marine Sedimentology and Environmental Geology,First Institute of Oceanography,Ministry of Natural Resources,Qingdao,Shandong 266061,China)

机构地区：[1]中国科学院大学,北京100049 [2]中国科学院南海海洋研究所,边缘海与大洋地质重点实验室,广州510301 [3]青岛海洋科学与技术国家实验室海洋地质与环境功能实验室,山东青岛266237 [4]海南大学海洋学院,海口570228 [5]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,山东青岛266061

出　　处：《矿物岩石地球化学通报》2023年第4期786-795,共10页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金资助项目(4216075,42130412,42206056)。

摘　　要：本文通过分析柱状沉积物E87-32B孔的稀土元素组成特征,探讨该孔陆源沉积物的源区,并进一步判别其ΣREE含量变化的古环境意义。结果显示,E87-32B孔沉积物的ΣREE含量为150.2~180.2μg/g。在经上地壳稀土元素标准化后,沉积物的稀土元素配分模式具有明显的Eu负异常,这与恒河-布拉马普特拉河源区最为接近,证实研究区的沉积物主要来源于恒河-布拉马普特拉河。沉积物的ΣREE含量与(Gd/Lu)UCC表明研究区存在少量印度半岛与伊洛瓦底江物质的输入。沉积物的ΣREE含量整体上表现出冰期-间冰期的变化特征。在冷期MIS 2阶段减弱的印度夏季风导致喜马拉雅系统降雨与侵蚀速率的降低,从而引起恒河-布拉马普特拉河源区的供给量减少,因此ΣREE含量处于低值区间,而在暖期MIS 1阶段则是与之相反的过程。In this paper,based on the analysis of REE compositional characteristics of columnar sediments from core sam-ples of Borehole E87-32B,we have discussed the provenance of continental sediments of core samples,and have further discriminated the paleoenvironmental significance for the variation of ΣREE contents in the sediments.The results indicate that the sediments from core samples of Borehole E87-32B have ZREE contents ranging from 150.2 to 180.2μg/g,with obvious Eu negative anomalies on the upper continental crust normalized REE distribution patterns which are mostly similar to those of sediments of the Ganges-Brahmaputra Rivers,confirming that the sediments in the study area were mainly sourced from the Ganges-Brahmaputra Rivers.Additionally,a small amount of materials sourced from the Indian Peninsu-lar and the Irrawaddy River are also identified based on the ΣREE contents and(Gd/Lu)ucc values of sediments from core samples.The ΣREE contents of sediments from core samples generally have variation characteristics of glacial and interglacial sediments.In the cold MIS 2 stage,the weakened Indian summer monsoon led to the decrease of rainfall and erosion rates in the Himalayan system,and then resulted in the reduction of material supply sourced from the Ganges-Brahmaputra Rivers into the Bay of Bengal.Thus,the ΣREE contents of sediments in the Bay of Bengal are mainly varied in a reletively low value range.However,an opposite process had happened in the warm MIS 1 stage.

关 键 词：孟加拉湾 稀土元素 沉积物 物质来源 印度夏季风 

分 类 号：P736.4[天文地球—海洋地质]