东太平洋北部胡安·德富卡洋中脊Mothra热液场硫化物烟囱体成矿物质来源:铅和硫同位素组成  

Lead and sulfur isotope constrains for metal sources of sulfide chimneys,Mothra hydrothermal field,Juan de Fuca Ridge,Nothern East Pacific Ocean

作　　者：董从芳[1,2,3] 周怀阳[1,2] 彭晓彤[1,2] 袁远 姚会强[5] 

机构地区：[1]中国科学院广州地球化学研究所,广东广州510640 [2]同济大学海洋学院海洋地质国家重点实验室,上海200092 [3]中国科学院研究生院,北京100049 [4]广西二一五地质队有限公司,广西柳州545006 [5]广州海洋地质调查局,广东广州510760

出　　处：《地球化学》2011年第2期163-170,共8页Geochimica

基　　金：国家自然科学基金重点项目(40532011)

摘　　要：对采自Mothra热液场Faulty Towers硫化物烟囱体群(47°57.447′N,129°06.568′W)的一个硫化物烟囱体进行了铅和硫同位素组成的研究工作。分析结果表明,铅同位素组成的分布范围为:206Pb/204Pb=18.665～18.828;207Pb/204Pb=15.460～15.607;208Pb/204Pb=37.961～38.401。沿着烟囱体壁从外到内,铅同位素组成变化呈现较强的规律性:烟囱体外壁的铅同位素组成具有高放射性成因的特点,烟囱体内壁和环绕流体通道的矿物具有较小的铅同位素组成。硫同位素组成变化范围为0.4‰～2.1‰。烟囱体外壁的白铁矿、闪锌矿更倾向于富集轻硫同位素,分别为0.5‰和1.0‰,纤锌矿的硫同位素组成变化相对均一,为1.3‰～2.1‰。综合铅和硫同位素组成特征,初步判断成矿物质来源主要受基底玄武岩的影响,并存在少量沉积物来源铅和硫的加入。The sulfide chimney collected from the Faulty Towers sulfide complexes in Mothra hydrothermal field （47°57447′N,129°06568′w） has been studied for lead and sulfur isotopic compositions. The range of lead isotopic compositions of the samples was：^206Pb/^204Pb=18.665～18.828;^207Pb/^204Pb=15.460～15.607;^208Pb/^204Pb=37.961～38.401. It is observed that lead isotopic compositions changed regularly across the chimney walls, with more radiogenic lead in the outer walls and lower lead isotope compositions in the inner walls and/or across the fluid channels. Sulfur isotopic compositions ranged from 0.4‰to 2.1‰. Marcasite （0.5‰） and sphalerite （1.0‰） from the outer walls were enriched in light sulfur isotopoe, and wurzite had comparatively uniform values ranging from 1.3‰ to 2.1‰. Both lead and sulfur isotope data suggested that substrate basalts were the main metal sources of hydrothermal fluids, with some sedimentary source input.

关 键 词：铅同位素组成 硫同位素组成 硫化物烟囱体 Mothra热液场 

分 类 号：P597[天文地球—地球化学]