西南印度洋中脊活动与非活动热液区沉积物元素地球化学特征对比  

Geochemical Contrast in Sediments from Active and Inactive hydrothermal Fields on the Southwest Indian Ridge

作　　者：宋备 苏新[1] 吕士辉[1] 倪建宇[2] 廖时理[2] 陶春辉[2] 胡茂康 李世云 于翀涵 SONG Bei;SU Xin;LU Shihui;NI Jianyu;LIAO Shili;TAO Chunhui;HU Maokang;LI Shiyun;YU Chonghan(School of Ocean Sciences,China University of Geosciences,Beijing100083,China;The Second Institute of Oceanography,State Oceanic Administration,Hangzhou,Zhejiang310012,China)

机构地区：[1]中国地质大学(北京)海洋学院,北京100083 [2]国家海洋局第二海洋研究所,浙江杭州310012

出　　处：《现代地质》2020年第1期130-140,共11页Geoscience

基　　金：中国大洋矿产资源研究开发协会“十三五”课题“硫化物合同区沉积物地球化学特征与找矿应用”(DY135-S1-1-08)

摘　　要：龙旂热液区与断桥热液区分别是西南印度洋中脊典型的活动与非活动热液区。为研究两区内表层沉积物地球化学特征,对共59件表层沉积物进行了元素地球化学测试,对其进行物质组分、富集系数与R型聚类等分析。结果表明:两区内普遍含较高的Ca、Sr、Ba等生源元素和Fe、Mg、Si、Al等围岩元素,而构造、围岩和热液活动等因素的不同,使两区沉积物的元素地球化学特征存在差异。龙旂区沉积物出现了源于超基性围岩的组分并体现在元素聚类组合中,其沉积物中热液富集相关元素Cu、Zn、Fe和Co等。断桥区更高的生源元素含量可能指示其热液活动停止后,主要受生物沉积作用的影响,该区热液相关元素与基性围岩联系紧密,表现出Pb与W的明显富集。The Longqi and Duanqiao areas are two typical active and inactive hydrothermal fields respectively on the ultra-slow spreading Southwest Indian Ridge(SWIR).For studying the geochemical features between these two regions,59 seafloor sediments are compared with the material compositions,enrichment factors(EFs)and cluster analysis after major and trace elements test.The results reveal that the two regions show similarities in high contents of biogenic(e.g.Ca,Sr and Ba)and surrounding rock elements(e.g.Fe,Mg,Si and Al),and differences in structure,surrounding rock condition and hydrothermal activities,leading to differential geochemical behaviors of their sediments.We found extra ultramafic rock components in the sediments of Longqi area,where sediments are relatively enrich in hydrothermal elements such as Cu,Zn,Fe and Co.The higher contents of biogenic components in the Duanqiao area,where the hydrothermal related elements are characterized by the obvious enrichment of Pb and W,reflect the biological sedimentation playing dominant roles after hydrothermal activities stopped.Furthermore,the R type cluster analysis gives expression to the extra ultramafic components solely in Longqi area and close connections between hydrothermal activities and mafic base rock in Duanqiao area.

关 键 词：西南印度洋中脊 活动与非活动热液区 沉积物 元素地球化学 

分 类 号：P736[天文地球—海洋地质]