华南地质2025，Vol.41Issue(2)：407-420,14.DOI:10.3969/j.issn.2097-0013.2025.02.014
桂北摩天岭岩体电气石矿物学特征及其对岩浆-热液演化示踪
Mineralogy of Tourmaline in the Motianling Pluton,North Guangxi:Insights into Magmatic-hydrothermal Evolution
摘要
Abstract
The Motianling pluton is one of the oldest uranium-related granites in southern China.However,the characteristics and properties of its post-magmatic fluid have not yet been sufficiently studied,which limits the in-depth understanding of its mineralization mechanism.Tourmaline can provide important clues for investigating magma-hydrothermal processes.In this study,systematic research was conducted on tourmaline from the Motianling rock mass using electron probe microanalysis,in-situ laser ablation analysis,and principal component analysis.The results show that the tourmaline in the Motianling rock mass can be classified into three types:disseminated tourmaline(Tur-1)formed during the late magmatic stage,quartz-tourmaline aggregates(Tur-2)formed during the magmatic-hydrothermal transition stage,and tourmaline-quartz veins(Tur-3)formed during the hydrothermal stage.These tourmalines exhibit distinct clustering features in major elements,with the vast majority being schorl.The study indicates that from Tur-1 to Tur-3,the formation environment of tourmaline transitions from magmatic to hydrothermal,with Tur-2 potentially recording this evolution process.The further increase in elements such as V and Co also suggests continuous fractional crystallization of the magma.The different types of tourmaline reflect the intensification of fluid activity and stage transition within the magmatic system.Meanwhile,the magmatic-hydrothermal fluid activity in the Motianling area plays a significant role in forming local uranium deposits(e.g.,Xincun and Daliang uranium deposits)and tin deposits(e.g.,Jiufeng tin deposit).The presence of volatile components not only enhances the magma's ability to enrich uranium but also further increases the uranium content in the main granitic body of Motianling,providing a substantial material basis for the formation of uraninite with the rock mass.When the Motianling granitic magma evolved to its late stage,it exsolved fluids rich in F and B,which provide both the heat source and Sn-F-B-enriched fluids essential for tin mineralization,thus offering sufficient ore-forming materials for the formation of the deposit.关键词
电气石/元素替换/主成分分析/岩浆-热液演化/摩天岭Key words
tourmaline/element replacement/Principal Component Analysis(PCA)/magma-hydrothermal evolution/Motianling分类
天文与地球科学引用本文复制引用
周心怡,王凯兴,刘晓东,朱坤贺,吴昆明,史竟存..桂北摩天岭岩体电气石矿物学特征及其对岩浆-热液演化示踪[J].华南地质,2025,41(2):407-420,14.基金项目
中国铀业有限公司-东华理工大学核资源与环境国家重点实验室联合创新基金项目(2023NRE-LH-01)、中国核工业地质局高校科研攻关项目(201619) （2023NRE-LH-01）
