Tungsten-Tin Mineralization and Its Dynamic Background in the Bozhushan Ore District, Southeastern Yunnan: Constraints From Petrology, Geochronology and Geochemistry

Abstract

The W–Sn–Ag–Pb–Zn polymetallic deposit in the Bozhushan ore concentration area is closely related to Late Cretaceous magmatic activity, and the diagenetic age of the granite body is 88.8–87.1 Ma. The granites in the Bozhushan ore district are characterized by high silica and aluminium contents, high abundances of Rb, Sr, Sn and Th, and low contents of Ba, P and Ti. The granites are peraluminous S-type granites that underwent fractional crystallization during magmatic evolution. The ε_Hf(t) values of the zircons from −17.92 to −1.77, with T_DM2 age ranging from 1.1 to 2.0 Ga, indicate that they may be mainly derived from partial melting of the lower crust without the addition of mantle-derived materials. The Late Cretaceous magmatic activity in the Bozhushan area formed in a syn-collisional tectonic environment and transitioned to a post-collisional orogenic environment. In the later stage, it transforms into a post-collisional extensional environment. The upwelling of deep-seated asthenospheric melts has provided substantial fluxes of W, Sn, Pb, Zn and other ore-forming elements. The ore-forming fluid and materials carried by magma rise and migrate along favourable parts of the structure to precipitate and mineralize. Therefore, understanding the tungsten-tin metallogenic history in the Bozhushan ore district is important.