| 扬子板块黔中地区绿豆岩锂富集机制研究 |
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| 关键词:GBRs lithium enrichment mechanism occurrence state Yangzi Platform |
| 基金项目:本文由国家重点研发计划项目(编号: 2021YFC2901905)、战略新兴产业矿产地质调查项目(编号: KD-[2025]-XZ-061)和战略性矿产成矿理论和找矿技术贵州省科技创新领军人才工作站项目(编号: KXJZ[2024]016)联合资助。 |
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| Lithium Enrichment Mechanism of Green Bean Rocks in the Central Guizhou Region of the Yangtze Plate |
| Green Bean Rocks (GBRs) represent a key marker layer of the Early to Middle Triassic (T1–T2) sea-land transition period of the Yangtze Plate. They are widely distributed within the tidal flat-lagoon-facies strata, such as the Jialingjiang and Leikoupo Formations, during the evolutionary stage of the passive continental margin of the Yangtze Platform. Their strata are stable and have unique mineral assemblages and geochemical characteristics. They are of great significance for the reconstruction of the tectonic-sedimentary evolution of the Indosinian period and exploration of Li resources. Recently, with the sharp increase in the demand for strategic minerals, GBRs have become an important carrier of sedimentary Li ores because of their Li-rich (127×10–6–800×10–6) characteristics. In this study, the central Guizhou region on the southwestern margin of the Yangtze Plate was considered as the research object. The genetic mechanism was revealed through systematic sampling and application of methods such as microscopic identification, X-ray diffraction, scanning electron microscopy, and energy spectrum analysis. Through the analysis of geochemical indicators of GBRs, the eruption of feldspar volcanoes was found to provide the initial products of volcanic ash. In the shallow marine-brackish water environment, volcanic ash rapidly eroded into montmorillonite, and the initial enrichment was formed through the interlayer adsorption of Li in montmorillonite. During the burial stage, the deep hydrothermal fluid carried Li upward, triggering the transformation of montmorillonite into illite. This process releases Li in the interlayer water and integrates it into the illite crystal. The Li in mung beans rock mainly exists in the form of isomorphic/adsorbed state in montmorillonite, illite, and illite/montmorillonite layers. With the increase in illite content, the Li content increases simultaneously. Its enrichment mechanism is closely related to the formation process of clay minerals and deep Li-rich fluids. The evaporation concentration and burial closure systems in the semi-confined tectonic basin jointly drive the continuous enrichment of Li, forming a multi-stage dynamic model of “volcanic ash alteration-fluid activation–mineral transformation”. Its mineralization efficiency is jointly regulated by temperature and salinity gradient and tectonic-sedimentary coupling (edge reef and beach isolation, rapid settlement, and storage). |
| YANG Qianmin,FU Yong,LUO Muhuan,TANG Bo,LIU Guodong,YANG Li,YANG Ying,LI Zhi,CHEN Lihong.2026.Lithium Enrichment Mechanism of Green Bean Rocks in the Central Guizhou Region of the Yangtze Plate[J].Acta Geoscientica Sinica,47(4):790-804. |
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