云南个旧锡多金属矿集区电气石地球化学组成和硼同位素特征——对成矿流体性质和演化的约束 |
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关键词:tourmaline B isotopes magma hydrothermal tin polymetallic deposits Gejiu tin mine cluster area |
基金项目:云南省科技计划项目(编号: 202202AG050006);云南省科技计划项目高层次科技人才及创新团队选拔专项(编号: 202305AT350004) |
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摘要: |
Geochemical Composition and Boron Isotope Characteristics of Tourmalines in the Gejiu Tin Polymetallic Mining Area, Yunnan Province: Constraints on the Properties and Evolution of Ore-forming Fluids |
The Gejiu tin deposit is a world-class Sn-Cu polymetallic deposit related to highly differentiated granite in the Late Cretaceous. Its mineral origin and fluid evolution process have always been the focus of research. Tourmaline is widely developed in carbonate rock, granite, and skarn in the Gejiu area; however, the relationship between tourmaline and mineralization is unclear. In this study, systematic petrographic observation and electron Microanalysis (EPMA), and LA-ICP-MS analysis of trace elements and boron isotopes from different types of tourmaline were carried out. The results show that all tourmalines belong to basic tourmaline; TurⅠ, TurⅡ, and TurⅣ are of hydrothermal origin, whereas TurⅢ is of magmatic origin. Compared with hydrothermal tourmaline, magmatic tourmaline has lower Mg, Ca, and other elements and the high Sr content of TurⅠ tourmaline indicates that it was contaminated by the surrounding rock. The variation in trace elements in the tourmaline reveals that Sn was gradually enriched in the magma and precipitated in the porphyritic granite and contact skarn, with an increasing degree of magmatic differentiation from porphyritic granite to equite-grained granite. The different types of tourmalines had uniform δ11B values (?15.2‰ – ?12.8‰), which are consistent with the composition range of granite, indicating that the ore-forming materials were derived from granitic magma. |
REN Hongyu,LI Chao,JIANG Xiaojun,YANG Fucheng,HAN Zhang,LU Lei,CHEN Yaokun.2024.Geochemical Composition and Boron Isotope Characteristics of Tourmalines in the Gejiu Tin Polymetallic Mining Area, Yunnan Province: Constraints on the Properties and Evolution of Ore-forming Fluids[J].Acta Geoscientica Sinica,45(4):575-590. |
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