西南印度洋脊49.6°E热液区热液产物和玄武岩地球化学特征  

Geochemical characteristics of hydrothermal deposits and basalts at 49.6°E on the Southwest Indian Ridge

作　　者：王振波[1,2] 武光海[1,2] 韩沉花[1,2] 

机构地区：[1]国家海洋局第二海洋研究所,浙江杭州310012 [2]国家海洋局海洋生态系统与生物地球化学重点实验室,浙江杭州310012

出　　处：《海洋学研究》2014年第1期64-73,共10页Journal of Marine Sciences

基　　金：中国大洋"十二五"重大项目资助(DY125-11-R-04);国家重点基础研究发展计划项目资助(2012CB417305);国家海洋局第二海洋研究所基本科研业务费项目资助(JG1216)

摘　　要：利用X射线荧光法和ICP-MS等方法对取自超慢速扩张的西南印度洋脊(SWIR)49.6°E热液区的热液产物和玄武岩样品进行元素地球化学特征分析研究,结果表明:(1)与亏损型洋中脊玄武岩(N-MORB)相比,研究区玄武岩样品的主量元素组成显示其偏碱性,而微量元素对比表明该区玄武岩明显富集Pb元素;(2)对热液产物的综合分析表明这些样品多为Fe-Si-Mn氧羟化物且都为热液来源;(3)热液产物的∑REE含量介于玄武岩和海水之间,经球粒陨石标准化的稀土元素(REE)分布模式均表现出Eu正异常和轻稀土(LREE)富集的特征。另外,本研究还表明,利用玄武岩和热液产物地球化学指标不仅能够模拟出以热液喷口为中心的元素地球化学晕,而且能反映出热液活动的影响范围。The geochemical characteristics of hydrothermal deposits and basalt samples taken from the ultraslow-spreading Southwest Indian Ridge at 49.6°E were analyzed by using XRF and ICP-MS. The results indicate. （1） the basalt samples in this area tend to be more alkaline comparing with the contents of the major elements of the N-type mid-ocean ridge basalts （N-MORB）, and they are richer in Pb element than the N- MORB comparing with the contents of the trace element （2） the analysis of major elements and trace elements of hydrothermal deposits indicates that the chosen samples are mostly Fe, Si, Mn-rich oxyhydroxide, and both of them are the hydrothermal origin~ and （3） the contents of REE in the hydrothermal deposits are between those in basalt and seawater, the chondrite-normalized REE patterns of the hydrothermal deposits are characterized by positive Eu anomalies and LREE enrichments, and the geochemical indicators can not only simulate the distribution of element halos center on the hydrothermal vent on a small scale, but also reflect the influence area of the nearest hydrothermal activity.

关 键 词：西南印度洋脊 玄武岩 热液产物 地球化学晕 

分 类 号：P744[天文地球—海洋科学] P736.3