Tin is a strategic key metal widely used in aerospace and high-tech industries. Worldwide, tin ore is mainly of magmatic hydrothermal type, and its formation is usually associated with highly differentiated reducing (ilmenite series) granite. However, the key factors that constrain the scale of tin ore formation have long been controversial; On the one hand, research suggests that tin is mainly retained in the melt during fluid leaching, and may crystallize directly in the form of magmatic cassiterite (SnO ₂), or first occur in minerals such as biotite, chalcopyrite, and ilmenite, and then form hydrothermal cassiterite through fluid leaching (Wei et al., 2024; Schmidt, 2018); On the other hand, recent experimental studies have shown that highly differentiated granitic melts can directly carry large amounts of tin in their fluids, forming hydrothermal tin deposits without the need for additional external fluids to participate in leaching (Zhao et al., 2022; Keppler and Aud é tat, 2025). The key controlling factors for the formation of large-scale tin mines caused by the above controversies are still unclear.