Genesis of Bangbu Orogenic Gold Deposit in Tibet: Constraints from Fluid Inclusions and Isotopic Composition
详细信息
- 责任者：Sun Qingzhong (Geological Survey of Jiangsu Province ; Nanjing 210018 ; China) ; Zheng Yuanchuan
- 刊名：Mineral Deposits
- 出版年：2013
- 卷期：32(2)
- 关键词：金矿 ; gold ores ; 石英脉型矿床 ; quartz veins type deposit ; 西藏 ; Tibet
- 页码：p.353-366
- 图表：illus., 2 tables, 52 refs.
- 分类号：1001
- issnNo：ISSN0258-7106
- isbnNo：CN11-1965/P
摘要
The Bangbu quartz-vein type gold deposit is located in Jiacha County,southern Tibet,lying in the southeastern segment of the Langjiexue accretionary wedge on the south side of the Yarlung-Zangbo suture.Muscovite Ar/Ar geochronological study indicates that it was formed at(49.5±0.5)Ma,consistent with the period of the onset of the Indo-Asian collision.The gold ore bodies are jointly controlled by the Jindi-Lunong synclinorium and Cuogu-Zhemulang large-scale brittle-ductile shear zone as well as its secondary structures.The mineralization of gold was mainly associated with quartz veins in the mining area.According to the attitudes,the quartz veins can be divided into three types,namely,the pre-metallogenic hook-like veins,the metallogenic large quartz veins and the post-metallogenic NS-striking quartz veins.The authors made microthermometric measurement,laser Raman analysis of fluid inclusions and H-O isotopic analysis of the three types of the quartz veins.Microthermometric measurements indicate that the three types of fluid inclusions in the Bangbu gold deposit are characterized by low salinity,low temperature and low density.Laser Raman analysis indicates that the inclusions in the pre-metallogenic hook-like quartz veins are dominated mainly by liquid,and H-O isotope analyses of these quartz veins indicate that the fluids trapped in the quartz were derived from regional metamorphism in the early phase.Inclusions in the mineralized large quartz veins are mainly VL inclusions characterized by larger volume.Analysis indicates that these inclusions mainly contain H2O+CO2+CH4±N2,and H-O isotopic data indicate that the ore-forming fluids were mainly derived from metamorphic fluids which were interacted with organic materials during their passing through the regional sedimentary strata.Fluid inclusions in the post-metallogenic quartz veins associated with STDS are chiefly VL inclusions in small volume and mainly contain H2O+CO2,and H-O isotopes,suggesting that these fluids might have resulted from post-ore metamorphism.The main mineralizing fluid was derived from the deep metamorphic fluid,and the main factor responsible for the deposition of Au was probably the boiling process.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |