四川盆地东部晚二叠世含煤岩系中锂富集机制：来自锂同位素的研究

Lithium, which is one of the important rare metals, with significant strategic value, and coal-bearing strata maybe one of the major resources of lithium. The previous research indicated that the Late Permian coal-bearing strata in the Eastern Sichuan Basin are highly-enriched with lithium. In this study, therefore using the lithium isotope method, and combination with the chemical analysis, Scanning Electron Microscope(SEM) and mineral phase analysis to determine lithium concentrations of the coal-bearing strata and tuffs located at the bottom of the strata from Wujiaping Formation in Yujiang, Lutang, and Luojiayuanzi coalfield, southeast Chongqing, Sichuan Basin. According to the above data, the temporal and spatial distribution of lithium and its modes of occurrence, the influence of geological process on the enrichment of lithium of the coal-bearing strata will be discussed. These results may provide scientific basis for exploration and development of lithium deposit in coal and coal-bearing strata.. The study on coal-hosted lithium deposit not only fully reflects the characteristics of national coal and rare metal resources, but also are practically significant for the sustainable development of coal and the security of national rare metal resources.

锂（Li）是重要的稀有金属之一，具有极高的战略价值，而含煤岩系可能是Li的主要来源之一。前期研究发现四川盆地东部晚二叠世含煤岩系中具有较高的Li含量。为此，本项目拟选取四川盆地东部的郁江煤矿、芦塘煤矿、罗家院子煤矿区为研究对象，通过高分辨率采取晚二叠世吴家坪组煤层及煤层底部凝灰岩样品，系统分析含煤岩系中Li含量及同位素组成特征，结合化学组成分析、扫描电镜和矿物相分析等手段，揭示含煤岩系中Li的时空分布规律、赋存状态及富集的地质地球化学机理，为进一步勘查开发煤型Li矿床提供科学依据，并为其它地区煤型Li矿床的研究提供参考资料。. 煤型Li稀有金属矿床的研究充分体现了我国煤炭和稀有金属资源特色，将为我国稀有金属资源安全和煤炭资源可持续发展起到重要作用。

锂（Li）是重要的稀有金属之一，具有极高的战略价值，含煤岩系可能是Li的主要来源之一，四川盆地东部晚二叠世含煤岩系中具有较高的Li含量。本项目以四川盆地东部的芦塘煤矿和桑柘煤矿为研究对象，采用扫描电镜、矿物相、化学组成分析及同位素组成特征等手段分析了晚二叠世含煤岩系中Li的时空分布规律、赋存状态、Li同位素组成及其富集机理。研究结果表明选择的两个煤矿晚二叠世煤层底部凝灰岩中富集Li，可能是一种潜在的新型煤型Li矿床；凝灰岩中主要矿物为高岭石、伊利石、鲕绿泥石、黄铁矿、锐钛矿等，锂主要以铝化合物结合态存在，鲕绿泥石是Li的矿物载体。凝灰岩中δ7Li值变化范围为10.11‰~10.93‰，平均值为10.51‰，与蚀变玄武岩锂同位素组成较一致。TiO2/Al2O3比值、微量元素特征及稀土元素配分模式揭示凝灰岩组成与峨眉山玄武岩有关。综合以上，认为物源区中火山喷发物质导致了四川盆地东部晚二叠世含煤岩系中锂高度富集，风化作用进一步导致锂富集。项目成果将为进一步勘查开发煤型Li矿床提供科学依据。