【摘要】 安徽省金寨县沙坪沟钼矿床是近年来秦岭—大别成矿带发现的超大型斑岩钼矿床,已探明钼资源储量246×10⁴t。通过对沙坪沟钼矿床不同勘探线剖面和不同深度代表性样品的S、H、O稳定同位素地球化学的研究,揭示了沙坪沟钼矿床S、H、O同位素组成特征及其空间分布特征。矿床硫化物硫同位素组成变化范围较窄,δ³⁴S变化于+0.4‰～+6.2‰,平均值为+3.47‰,落在火成岩范围,分布具明显的塔式效应,硫的来源比较均一,主要为深源硫。成矿流体的δ¹⁸O_包裹体水为0.40‰～7.52‰。流体包裹体中δD变化范围为-90‰～-63‰。主成矿期成矿流体总体为岩浆水。在不同勘探线剖面上矿化中心具高的δ³⁴S、δ¹⁸O值,而且显示出从深部钠长石—钾长石—硅化带→黄铁绢英岩化带→浅部的绿泥石—碳酸盐化带δ³⁴S、δ¹⁸O值有降低的趋势。上述特征表明沙坪沟钼矿床主成矿期成矿环境由碱性向酸性过渡,且没有发生明显的低δ¹⁸O作用,成矿环境相对封闭,外部对流循环的雨水系统参与成矿作用程度相对较小,与东秦岭其他斑岩钼矿床不同。更多还原

【Abstract】 Shapinggou molybdenum deposit,Jinzhai County,Anhui Province,is a super large porphyry molybdenum deposit discovered in the Qinling-Dabie metallogenic belt in recent years. The proven reserves of molybdenum resources are 246×10⁴ t. The S,H,O stable isotopes for representative samples from different prospecting line sections at various depths were analyzed in this paper. The sulfur isotopic composition of sulfides in the ore deposit varies in a narrow range from +0.4‰ to +6.2‰. The average value is +3.47‰ within the range of igneous rocks,showing Gaussian distribution in histogram. The source of sulfur is relatively uniform,mainly deep sourced sulfur. The δ¹⁸O value of ore-forming fluid inclusions ranges from 0.40‰ to 7.52‰,and δD value of fluid inclusions ranges from -90‰ to -63‰,which suggest that ore-forming fluid for main mineralization resulted from magma. High δ³⁴S and δ¹⁸O values correspond to mineralization central zone at various prospecting line sections. Besides,the δ³⁴S and δ¹⁸O values have a decreasing tendency from albite feldspar-potassium feldspar-silicified zone,beresitization zone to chlorite-carbonation zone. The above characteristics indicate that the geochemical environment of ore-forming fluid of Shapinggou molybdenum deposit changed from alkaline into acidity during the main ore-forming period. There is no obvious low δ¹⁸O effect,the ore-forming occurred in a quite closed environment,and meteoric water with external convection circulation is relatively less involved in the mineralization. The geochemical environment is different from other porphyry molybdenum deposits in the East Qinling district.更多还原