陕西旬阳公馆—青铜沟汞锑矿床地球化学研究

Geochemistry of Gongguan-Qingtonggou Hg-Sb deposit in Xunyang,Shaanxi Province

陕西旬阳公馆—青铜沟汞锑矿床位于南秦岭东部,矿床受赋矿的泥盆纪白云岩地层和发育于其中的断裂的双重控制,矿体呈脉状,矿石主要由辉锑矿、辰砂、石英、方解石组成。氢氧同位素研究表明,该矿床的成矿流体为大气水。碳氧同位素显示热液方解石的形成与地层碳酸盐关系密切,并有少量有机碳参与成矿。矿石硫来源于地层中硫化物的分解或硫酸盐的还原作用。锶、铅同位素研究表明其与成矿物质汞、锑共同来源于下覆基底地层。综合研究表明公馆-青铜沟汞锑矿是一种受断裂控制的脉状矿床。

Gongguan-Qingtonggou Hg-Sb deposit in Xunyang,Shaanxi Province is controlled by both strata and faults,and ore bodies occur in the faults at each level in the dolomite of the Devonian Gongguan formation.Hydrogen and oxygen isotopic study indicates that the ore-forming fluid is dominated by meteoric water.Carbon and oxygen isotopes reveal that the formation of hydrothermal calcite is closely related to the strata.The carbon isotope composition of the hydrothermal calcite is not completely consistent with that of ore-bearing strata due to the organic carbon in the strata mixed with the ore-forming fluid.Moreover,the sulfur is derived from the decomposition of sulfide or the reduction of sulfate in the strata while the lead is derived from a deep source and displays the characteristics of lead isotope in orogenic belt.Sr isotopes in ores and wall rocks indicate that the main ore-forming material such as Hg and Sb is carried by the fluid with high ^87Sr/^86Sr value that is derived from a deep source.