【摘要】 湘黔新晃—天柱地区的早寒武世重晶石成矿带是世界上最大的重晶石矿集区,在全球范围内具有代表性,对其进行研究具有重要的科学意义。本文通过对新晃—天柱地区的重晶石矿床微量稀土元素和硫同位素研究表明:所有样品的V/Cr、U/Th比值以及重晶石含矿岩系稀土元素具有明显的Ce负异常表明重晶石矿床形成时处于缺氧还原环境;重晶石矿石表现出明显的Eu正异常,反映了成矿过程受到了较强的海底热液物质的影响,表明钡可能主要来自于海底热液喷流物质;重晶石的δ34S值主要分布在+40‰⁺45‰,表现出重硫富集的特征,且重晶石硫同位素呈塔式分布,表明硫源来源单一,主要来自同期海水硫酸盐。黄铁矿δ³⁴S值低于同期海水硫同位素组成,表明生物细菌对海水硫酸盐的还原起到了很大作用,并且反映了矿床形成于海水交换有限的滞留的海盆系统。综合以上分析认为重晶石成矿时期为海底缺氧、热液活动频繁、封闭-半封闭的台地泻湖环境。更多还原

【Abstract】 The barite deposits formed in the early Cambrian in Xinhuang and Tianzhu are the largest barite deposit in the world and arerepresentative in the global scope. This study carried out the rare earth elements and sulfur isotope analyses of these barite deposits.Allthe sample’s V/Cr and U/Th values and the Ce negative anomaly implied that the deposits were formed in anaerobic and reductionenvironment. The rare earth elements of barite have obviously Euelement positive anomaly, indicating that the ore-forming process wasstrongly affected by the seafloor hydrothemal fluid and the source of the barium is mainly from the seafloor hydrothemal material; Thesulfur isotope composition of BaSO₄ mainly ranged from +40‰ to +45‰,enriched in ³⁴S and the sulfur isotope of BaSO₄ is characterizedby tower style distribution, which indicates that the source of sulfur is of single-source and from the seawater sulfate. The δ³⁴S of pyriteis lower than the δ³⁴S of the contemporary sea water, indicating that biological bacteria played an important role in the sulfate reductionin the seawater and imply that the barite deposit formed in an environment where there is limited seawater exchange. Based on the above analysis, the barite deposit was formed in a semiclosed-closed lagoonal and anaerobic environment where there are frequentseafloor hydrothermal activities.更多还原