祁雨沟金矿田S、O、C、Pb同位素组成及成矿物质来源

祁雨沟金矿田是由以隐爆角砾岩型为主、石英脉型、构造破碎带蚀变岩型和斑岩－角砾岩型等金矿床组成的一个成矿亚系列．该矿田硫同位素组成变化范围较窄，δ３４ＳΣＳ＝－０．１７‰，硫来源于深沉岩浆；氧同位素变化范围为－４．３１％０～４．６０‰，主成矿期与幔源岩浆水氧同位素值相近，晚期出现负值，表明有大气降水参与成矿；成矿晚期联同位素的δ１３ＣΣＣ＝－３．８３‰，为岩浆碳与地层碳酸盐不同比例混合的结果；铅同位素研究表明．矿床铅为正常铅混合型，μ值较低，成矿铅主要来源于岩浆，有少量地层铅混入．经同位素、构造、地层、岩浆岩、矿物微量元素和包裹体等综合研究，表明本区金矿成矿物质主要来自壳幔层同熔的燕山期花岗质钙碱性岩浆，部分来自上地壳太华群变质岩．

S,O,C AND Pb ISOTOPE COMPOSITION AND SOURCES OF ORE-FORMING MATERIALS OF QIYUGOU GOLD DEPOSITS

iyugou gold deposits are composed of a metallogenic series,which includes cryptoexplosive breccia type (main type),quartz-veins,structurally fractured metasomatic and porphyry-breccia types. The variation limit of sulfur isotope value is narrow(δ34SΣs= 0.17‰) and the sulfur was from deep source magma.δ18OH2O=-4.31‰～4.60‰,and the hydrothermal fluid of the main mineralization period is close to magmatic fluid.Negative value appears in the late period, which suggests that rain water added at late mineralization.δ13CΣC=-3.83‰,in the late mineralization period,shows that the magmatic carbon was mixed with strata carbon.Isotope analysis of lead suggests that the lead of these deposits belongs to the mixed type of normal-lead,which was mainly from magama,but mixed with a little strata lead.Systematic researches of isotopes,structures,strata,magama,microelements and inclusions reveal that the majority of the ore-forming elements are from cafe-alkaline granite rocks of mid-late Yanshan Epoch,which originated from upper mantle and low crust,few provided by strata of Archean Taihua Group.The ore-forming materials are multi-source.