Analysis of ore-bearing formations, mineralization processes, and exploration potential of weathering crust ion-adsorption type rare earth deposits in Southern Jiangxi, China

Objective Southern Jiangxi Province (Gannan) represents China's most significant resource base for weathering crust eluvial-type rare earth element (REE) deposits, hosting major and supergiant REE deposits including Zudong, Shitouping, and Heling. However, systematic studies on the ore−bearing formations and mineralization processes of these deposit types remain limited.

Methods This study draws upon extensive rare earth exploration and research findings accumulated over many years, conducting comprehensive analysis and synthesis of geological, geochemical, and drilling data. The research aims to elucidate the ore-bearing formations and mineralization processes of weathering crust eluvial−type REE deposits in Southern Jiangxi Province.

Results Based on genetic classification, the rare earth ore−bearing formations in Gannan can be divided into intermediate−acidic granite ore−bearing formations, volcanic rock ore−bearing formations, metamorphic rock ore−bearing formations, and migmatite ore−bearing formations. These formations have different rock characteristics. Although the formation process of weathered crust leaching−type rare earth deposits shows similarities, the deposit distribution types exhibit significant differences. The parent rocks of heavy rare earth deposits are mainly from the Early Yanshanian and Late Yanshanian periods, while light rare earth deposits show no exclusive temporal preference, as granites from various periods can form light rare earth deposits. Heavy rare earth mineralization occurs through two mechanisms: heavy rare earth−enriched parent rocks weathering to form heavy rare earth ores, and Y−rich light rare earth−enriched parent rocks weathering to form heavy rare earth ores. Generally, the rare earth content in ore−forming parent rocks is not less than 82 × 10⁻⁶. Additionally, supergene mineralization processes are also key factors controlling rare earth mineralization. Weathered crust leaching−type rare earth deposits exhibit characteristics of "endogenous origin and exogenous formation."

Conclusions Gannan is characterized by "abundant rare earth element material sources, strong weathering processes, and favorable deposit preservation conditions." In recent years, the successive discoveries of the Shitouping and Xiahu−Dabu super−large heavy rare earth deposits demonstrate that significant exploration potential still exists.