安徽朝山金矿床矿石含金性和硫同位素研究

朝山金矿床位于铜陵市东郊狮子山矿田内。除了自然金之外,矿床中金主要以晶格金方式赋存于磁黄铁矿、黄铁矿和毒砂等矿石矿物之中;各种类型矿石成矿元素研究表明,含金磁黄铁矿石中金含量最高,其他依次为含金磁黄铁矿—黄铁矿矿石、含金黄铁矿化大理岩、含金矽卡岩、含金黄铁矿矿石等;硫同位素分析显示矿石硫主要来自深源或幔源硫,但在上升过程中遭受到地壳物质混染。在上述研究基础上,综合前人研究成果及朝山金矿地质特征,表明朝山金矿床属于热液交代型金矿床,形成时代为燕山中晚期。

Gold bearing property and sulfur isotopic compositions of ore rocks at Chaoshan gold deposit, Anhui

The occurrence of gold in Chaoshan gold deposit which is located in Shizishan ore-field in the east of Tongling,is mainly ionic gold(lattice gold)in ore minerals such as pyrrhotite,pyrite and arsenopyrites,besides native gold.Electronic Microprobe Analysis(EMPA)study on metallogenic element concentrations of main ore minerals and relevant study on ore forming element concentrations of various types of ore rocks,indicate that the gold concentration in gold bearing pyrrhotite ores is the highest,and that of gold bearing pyrite-pyrrhotite ores,gold bearing marbles with pyritization,gold bearing skarn,and gold bearing pyrite ores decrease successively.Sulfur isotopic compositions of ore rocks suggest the sulfur in ore rocks are derived from furtherr deep source,maybe the mantle,and the proportion of sulfur from the crust was assimilated in the course ore forming process.Based on these new evidence and former relevant study,it is concluded that Chaoshan gold deposit is a middle-late Yanshanian hydrothermo-metasomatic gold deposit.