摘要
闽北政和-建瓯矿集区内大药坑金矿床是一个赋存于韧性剪切带中的小型矿床。在野外地质调查基础上,通过分析载金矿物黄铁矿电子探针成分和硫化物硫、铅同位素组成,探讨了大药坑金矿床的成矿作用问题。研究表明,大药坑金矿床黄铁矿的Co/Ni比值大多在1~5之间,为岩浆热液成因黄铁矿,成矿热液的温度和盐度均较高,也表现出岩浆热液的性质;金属硫化物的δ^(34) SCDT均为靠近0的较低正值(0.1‰~3.4‰),说明成矿物质为岩浆来源,硫化物的铅同位素比值以及高μ(^(238)U/^(204)Pb)和ω(^(232)Th/^(204)Pb)等特征,说明成矿物质具有壳幔混源特征。结合区域研究资料,认为大药坑金矿床形成于东南沿海区域强烈壳幔作用时期,与燕山期火山-侵入杂岩有关,矿床成因类型为岩浆期后热液型。
The Dayaokeng deposit located in the Zhenghe-Jianou ore concentration area is a small-sized gold deposit hosted by ductile shear zone.To investigate metallogenesis of the Daoyaokeng gold deposit,the authors carried out some experiments including EPMA and S-Pb isotopes.Most Co/Ni ratios of pyrites are 1 - 5 and,furthermore,the temperature and salinity of fluids are both high,suggesting magmatic hydrothermal origin.δ34SCDTvalues of pyrite,sphalerite,galenite are 2.7‰ - 3.4‰,2.2‰ and 0.1‰ - 0.5‰,respectively,which are positive values close to0‰( δ-(34)SCDTvalue of troilite),so it is reasonable that metal materials originated from magma.Pb isotope ratios of sulfide are 18.237 - 18.557(-(206)Pb/-(204)Pb),15.628 - 15.799(-(207)Pb/-(204)Pb) and 38.446 - 38.988(-(208)Pb/-(204)Pb)respectively; in addition,μ(-(238)U/-(204)Pb) and ω(-(232)Th/-(204)Pb) are high,suggesting that the ore-forming materials might have resulted from mixing of ore-forming materials derived from the crust and the mantle.Combined with previous regional researches,the authors hold that the Yanshanian volcanic-intrusive complexes had a close relationship with the Dayaokeng gold deposit,the deposit was developed at the stage of strong crust-mantle interaction of southeast coast block,and the metallogenic type of the gold deposit is postmagmatic hydrothermal type.
作者
肖凡
班宜忠
XIAO Fan BAN YiZhong(Nanjing Center, China Geological Survey, Nanjing 210016, Jiangsu, China)
出处
《矿床地质》
CAS
CSCD
北大核心
2017年第1期171-184,共14页
Mineral Deposits
基金
中国地质调查局地质调查项目"武夷山成矿带龙泉-上杭地区地质矿产调查"(编号:DD20160037)和"中国矿产地质与成矿规律综合集成和服务(矿产地质志)"(编号:DD20160346)资助
关键词
地质学
韧性剪切带
岩浆期后热液
金矿床
闽北
geology
ductile shear zone
postmagmatic hydrothermal
gold deposit
northern Fujian