摘要
湾岛金矿是近年来广西东南部大瑶山多金属成矿集中区古袍金矿田内发现的中型矿床,其物质来源及成因尚存在较大分歧。根据详细的坑道及岩矿相学观察,将湾岛金矿成矿分为2期3阶段:钨钼铜金成矿期和金主成矿期(分为金主成矿阶段和金晚成矿阶段)。石英流体包裹体显微测温和激光拉曼光谱分析表明,金主成矿期成矿流体为中高温、低盐度、低密度的含CO_2和CH_4流体。氢氧同位素分析表明,金主成矿期成矿流体中水主要为变质水,钨钼铜金成矿期成矿流体中水可能为岩浆水及变质水的混合。矿石矿物硫同位素数据显示,钨钼铜金成矿期硫同位素值为小的正值,可能为深源硫;金主成矿期湾岛矿区硫同位素组成变化范围大而均值较小,推测钨钼铜金成矿期成矿物质来源以深源硫为主;金主成矿期为岩浆硫与地层硫的混合硫。初步认为湾岛金矿属于变质-岩浆热液叠加改造成矿。
The Wandao gold deposit,located in Gupao ore field of Dayaoshan polymetallic metallogenic clusters area in the southeastern Guangxi,is a medium-sized ore deposit discovered in recent years.The source of oreforming substance and ore genesis are still under debate.There is still a big difference between its material origin and genesis.Based on detailed observation in underground tunnel and petrographic study under microscope,the Wandao gold deposit can be divided into W-Mo-Cu-Au mineralization period and main gold dominated mineralization period.Furthermore,the main gold dominated mineralization period can be divided into main stage and late stage.Microscopic temperature measurements and Laser Raman Spectra analysis of fluid inclusions in quartz indicate that the ore-forming fluids of main gold dominated mineralization period in the Wandao gold deposit are fluids with high temperature,low salinity,low density and containing CO_2 and CH_4.Hydrogen and oxygen isotope analysis data of quartz indicate the ore-forming fluids of main gold dominated mineralization period mainly derived from metamorphic water,and the ore-forming fluids of W-Mo-Cu-Au mineralization period is the mixture of magmatic water and metamorphic water.The small positive value of sulfur isotope for W-Mo-Cu-Aumineralization period infers that sulfur come from magma reservoir in depth.Whereas,small average with large range of sulfur isotopic composition for gold dominated mineralization period suggests that the sulfur in ore probably mainly derived from strata and partly from magmatic rocks.Based on the above analysis,it is considered that the Wandao gold deposit belongs to metamorphic and magmatic hydrothermal superimposed deposit type.
出处
《现代地质》
CAS
CSCD
北大核心
2017年第5期1006-1021,共16页
Geoscience
基金
国家自然科学基金项目(41362006)
中国地质调查局地质调查工作项目(12120114052501)
广西自然科学基金项目(2015GXNSFDA139029
2014GXNSFBA118230)
关键词
稳定同位素
流体包裹体
成矿流体
湾岛金矿
广西
stable isotope
fluid inclusion
ore-forming fluid
Wandao gold deposit
Guangxi
