金属硫化物矿床的成矿热液硫同位素示踪

Sulfur Isotope Tracing of Ore-forming Hydrothermal Fluid for Metallic Sulfide Deposit

国内外诸多学者对如何利用硫同位素来示踪金属硫化物矿床中硫的来源进行了不断的探索研究,并取得了丰硕成果。在总结金属硫化物矿床中含硫热液矿物的硫同位素组成(δ^(34)S)特征基础上,阐述了准确确定成矿流体的总硫同位素组成(δ^(34)S∑S值)是判别金属硫化物矿床中硫来源的关键,并总结和简要评述了获取成矿流体δ^(34)S∑S的3种方法(物理—化学平衡分析法、矿物共生组合分析法和Pinckey-Rafter法)以及应用实例。据此指出3点:1在应用硫同位素示踪硫的来源时,须针对不同类型金属硫化物矿床的具体特征,选择合适的方法以便成功获取δ^(34)S∑S;2目前δ^(34)S∑S的获取方法和应用基础是硫同位素的分馏达到平衡状态,对于低温或快速侵位条件下可能形成的非平衡状态的含硫热液矿物的δ^(34)S的特征仍待深入研究;3分别研究不同形态硫的δ^(34)S,并讨论不同形态硫的来源、形成环境和过程是一个新的发展趋势,对示踪金属硫化物矿床的硫源可能更为有效和有意义。

How to utilize sulfur isotope for many domestic and foreign researchers to trace the sulfur source of metallic sulfide deposit has been explored for many years. Fruitful results have been gained now. Based on summing up the characteristics of sulfur isotopic composition of hydrothermal mineral from metallic sulfide deposits,this paper illuminated the total sulfur isotopic composition of ore-forming fluids is the key factor in estimating the sulfur source. This paper also summarized three approaches about how to obtain the total sulfur isotopic composition（ δ34S∑S） of ore-forming fluids. They are physical-chemical equilibrium analysis,mineral paragenetic association analysis and Pinckey-Rafter,respectively. We gave some applied examples and made a brief comment of them as well. There are three points worth noting. Firstly,choosing appropriate approach is a critical factor to acquire theδ34S∑Ssuccessfully according to the characteristics of different types of metallic sulfide deposit. Secondly,currently,these above mentioned approaches and applications are effective after the establishment of equilibrium state of sulfur isotope. As to the sulfur isotopic disequilibrium condition in metallic sulfide deposits probably resulted from lower temperature or rapid emplacement,there are quite some problems in theory and technique. Therefore,an indepth study should also be continued. Thirdly,it is a new development trend to study isotope composition of different forms of sulfur and to discuss their source,forming environment and process respectively,which is probably more effective and significant for tracing sulfur sources of metallic sulfide deposits.