Magma fractionation and the magmatic-meteoric fluids mixing drive the sequential deposition of cassiterite to lepidolite in the Uljin prospects, South Korea

Several Sn Li prospects in the Uljin area, which is in the eastern part of South Korea, including Dongseok, Yuchang, Buguk, Chomak, Hyundong, and Boam, contain sub-economic cassiterite and Li-bearing silicate minerals such as lepidolite and spodumene, and phosphate mineral such as amblygonite, along with accessory Nb-Ta-bearing minerals. Among these, Dongseok and Yuchang are Sn-dominant, Buguk, Hyundong, and Chomak exhibit mixed Sn Li mineralization, while Boam (Western, Main, Eastern) is Li-rich. The Sn Li mineralization is associated with a series of hydrothermal alterations, particularly greisenization and albitization. Two stages of greisenization have been identified, with albite alteration occurring between them. Cassiterite (± Nb Ta minerals) precipitated during early greisenization (Greisen I), whereas spodumene crystallized as a primary mineral in subsequent pegmatite intrusion,…