摘要
研究区13个金矿床／点，24个自然金样品，161个点的电子探针测试表明，区内自然金成色平均值几乎均大于900％0，属高成色；自形晶比它形晶的金银含量均匀；位于交代前峰的金成色比尾部低，包体金随主矿物的种类不同成色不同。银是金中最主要的杂质元素；铋在该区金中具有很高的富集程度，是影响成色的主要因素。本区与湖南相比，具有地层越老、成色越高、银含量越低的共同规律，而成色高低与成矿时间和温度的关系较前人总结的规律出入甚大；比值关系表明，前者变化范围很小，后者很大，碱金属含量变化对前者影响不大。
The nature and composition of gold from 13 quartz-vein endogenic gold deposits and oc-currences in eastern Guizhou have been studied by optical microscopy and electron microprobe anal-ysis. A total of 16l analyses were per formed on gold grains in 24 samples. The results of the studyshow that gold from this area generally has high fineness, averaging almost>9OO%,. Gold finenessshows some variations in different samples and gold grains from the same deposit (up to 19. 48%,mostly between 3% ~ 5% ), but is more uniform within individual euhedral grains. Some within-sample variation appears to be related to the type of enclosed sulfide minerals. Ag is the main for-eign element in the gold. Bi shows a high enrichment coefficient in gold from the eastern Guizhouarea. The data on gold fineness, together with comparative data from similar deposits in Hunan,suggest a relationship between average gold fineness and the age of the host strata in this region.Deposits in older host rocks contain gold of higher fineness. Relationships between gold finenessand age or temperature of mineralization are different from those previously described. Fluid inclu-sion data show a large variation in Na/(Na+K) ratio in the ore fluids of different deposits, butthis is not reflected in systematic variation in Au/(Au+Ag) ratio, as suggested by previous stud-ies of some other deposits.
出处
《矿物学报》
CAS
CSCD
北大核心
1997年第2期175-182,共8页
Acta Mineralogica Sinica
基金
国家自然科学基金!49162010
关键词
内生金矿
成色
黔东
金矿床
成矿时间
endogenic gold deposit
fineness of gold
eastern Guizhou
