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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。
Lead and sulfur isotopic compositions of a sulfide chimney collected from Faulty Towers sulfide stacks (47 ° 57.447’N, 129 ° 06.568’W) in the Mothra Thermal Field were studied. The results show that the distribution range of Pb isotope composition is: 206Pb / 204Pb = 18.665-18.828; 207Pb / 204Pb = 15.460-15.607; 208Pb / 204Pb = 37.961- 38.401. Along the chimney body wall from outside to inside, the variation of lead isotope composition shows a strong regularity: the lead isotope composition of the outer wall of the chimney has the characteristics of high radiogenicity. The inner wall of the chimney and the minerals surrounding the fluid channel have smaller lead isotopes composition. Sulfur isotope composition of the range of 0.4 ‰ ~ 2.1 ‰. The white iron ore and sphalerite in the outer wall of the chimney are more likely to be enriched in light sulfur isotopes, 0.5 ‰ and 1.0 ‰, respectively. The sulfur isotopic composition of wurtzite is relatively uniform, ranging from 1.3 ‰ to 2.1 ‰. Based on the characteristics of lead and sulfur isotopic compositions, it is initially concluded that the source of metallogenic material is mainly affected by basal basalts, and there is a small amount of lead and sulfur added from sediments.