Magmatic controls and chronology of tin mineralization in the Mengsong Deposit, Southern Lincang Batholith, SW China

The Triassic Lincang granite batholith in southwestern Yunnan, China, hosts numerous granite-related tin deposits. This study investigates the Mengsong tin deposit, located in the southern part of the Lincang batholith, by integrating zircon UPb geochronology, Hf isotopic analysis, and trace element geochemistry. Zircon from the Mengsong deposit reveals crystallization ages of 225.5 ± 0.9 Ma (MSWD = 2.3, n = 20) for the muscovite granite and 224.7 ± 0.9 Ma (MSWD = 1.9, n = 25) for the two-mica granite. This indicates that the Mengsong granites was formed during the Triassic period. Zircon trace element signatures indicate that the Mengsong granites are highly fractionated and crystallized from magmas with low oxygen fugacity (ΔFMQ). Negative zircon ε_Hf(t) values (−14.3 to −1.5) indicate derivation from an ancient crustal source. We propose that reduced magmas were fundamental prerequisite for tin enrichment. This factor, in conjunction with highly magmatic differentiation of crustal melts generated during post-collisional extension after the Paleo-Tethys closure, created the ideal conditions for Sn mineralization. These results highlight the genetic relationship between tin mineralization and synchronous granitic magmatism in the Mengsong deposit and provide valuable insights for future exploration targeting Triassic tin systems in southwestern Yunnan.