Geological Characteristics and Genetic Analysis of Typical Tin–Polymetallic Deposits in the Teng–Liang Tin Belt

This chapter focuses on three typical tin–polymetallic deposits within the Tengchong–Lianghe Tin Belt—Jiaojiguan, Xiaolonghe, and Lailaishan–Siguangping—and systematically analyzes their geological characteristics, metallogenic ages, and genetic mechanisms. Research indicates that the Jiaojiguan deposit is an Early Cretaceous (122 ± 0.7 Ma) skarn-type iron–tin polymetallic deposit. Its mineralization is closely associated with that of monzogranitic porphyry, with the ore-forming fluids being predominantly magmatic–hydrothermal in origin. The Xiaolonghe deposit formed in the Late Cretaceous (70.6 ± 0.4 Ma) and is classified as a greisen-type tin deposit. The ore-forming process involved stages of potassic alteration, albitization, and greisenization, with meteoric water mixing into the fluid system during the middle to late stages of its evolution. The Lailaishan–Siguangping deposit formed during the Paleogene (50.3 ± 0.5 Ma), is significantly controlled by faults, and derived its ore-forming fluids from magmatic–hydrothermal sources, with later overprinting by low-temperature hydrothermal fluids. Integrated evidence from mineral paragenesis, fluid inclusions, and isotope geochemistry reveals that the tin–polymetallic mineralization in this belt is closely related to multiphase Mesozoic to Cenozoic magmatic activities exhibiting typical magmatic–hydrothermal metallogenic characteristics.