Geological Characteristics and Genesis of the Xialonggang Lead‐Zinc‐Antimony Deposit in South Tibet

Abstract The Xialonggang Pb‐Zn‐Sb deposit is a newly discovered large‐scale polymetallic deposit within the Tethyan Himalayan metallogenic belt. Although significant prospecting breakthroughs have been made at Xialonggang in recent years, the geology and mineralization process are poorly understood. This study conducted monazite U‐Pb geochronology, fluid inclusion, and O‐H‐S isotope of the Xialonggang Pb‐Zn‐Sb deposit. Analytical results indicate that the ore‐forming fluids constituted a H 2 O‐NaCl‐CO 2 ‐CH 4 ‐N 2 system characterized by moderate temperatures (261–314°C) and moderate to low salinities (2.9–8.9 wt% NaCl eqv.). The early‐stage fluids exhibited signatures close to magmatic fluids, while the late‐stage fluids showed characteristics indicative of mixing between magmatic fluids and meteoric water. Sulfur isotope analysis (mainly range primarily from 1.2‰ to 6.44‰, with one sphalerite up to 8.19‰) revealed that a predominantly deep‐sourced sulfur composition with minor contribution from sedimentary strata. This study demonstrates that the Xialonggang Pb‐Zn‐Sb deposit is controlled by the NE‐trending fault system. A hydrothermal circulation system driven by substantial deep‐seated magmatic heat, leached materials from the surrounding strata. The hydrothermal fluids migrated upwards along the fault system, filling the NE‐trending tensional fractures to form a hydrothermal vein‐type Pb‐Zn‐Sb deposit.