The Sn granites are characterized by biotite and titanite as Sn-bearing minerals, which suffured hydrothermal alteration, leading to tin leaching and subsequent crystallization of cassiterite.

• 前者以黑云母、榍石为典型含锡矿物，它们在流体富集阶段，经热液蚀变作用，导致锡的淋滤和结晶富集作用；