Metallogenic Patterns and Regional Comparison of the Western Yunnan Tin Belt

Focusing on the western Yunnan Tin Belt, this chapter systematically synthesizes the geological characteristics of 227 regional plutons and 16 typical tin deposits, revealing the metallogenic patterns of tin–polymetallic mineralization in western Yunnan. The results of this study indicate that the Western Yunnan Tin Belt is primarily controlled by the Mesozoic to Neo-Tethyan tectonic evolution. The tin-bearing granites are predominantly highly fractionated, S-type anatectic granites, with metallogenic epochs concentrated from the Late Yanshanian to Early Himalayan periods (140–50 Ma). Comparisons with the Southeastern Yunnan Tin Belt and the Bangong Lake–Nujiang Metallogenic Belt reveal that southeastern Yunnan is dominated by skarn-type cassiterite-sulfide deposits. These deposits formed in a lithospheric extensional setting within a concentrated metallogenic timeframe (93–78 Ma) and were significantly influenced by crust–mantle interactions. In contrast, western Yunnan is characterized by greisen-type cassiterite–quartz deposits, which formed in an intracontinental collision to postcollisional environment with a broader metallogenic age range. The Bangong Lake–Nujiang Belt features porphyry–skarn-type Cu–Au–Fe deposits, which differ significantly from those of western Yunnan in terms of the metallogenic setting and elemental association. A comprehensive comparison suggests that while both the Western Yunnan Tin Belt and the Bangong Lake–Nujiang Belt may belong to the Mesotethyan metallogenic domain, western Yunnan displays greater tin specialization and is characterized by intracrustal anatectic origins. This research provides a theoretical foundation and exploration guidance for regional tin prospecting.