Newly recognized Jurassic magmatic-hydrothermal gold mineralization at Wangmushan, South China: Geochronological and geochemical constraints

• Ap2 U–Pb ages (∼150 Ma) date Jurassic gold at Wangmushan. • Fluid mixing and water–rock interaction controlled Au mineralization. • Wangmushan differs from Cretaceous deposits, guiding exploration. The Wangmushan gold deposit, located in the Zhenghe region of the Southeast China Volcanic Belt (SCVB), is hosted by Proterozoic metamorphic rocks and Jurassic volcanic-subvolcanic rocks. Mineralization at Wangmushan occurred in two stages, each associated with distinct apatite generations: early-ore stage Ap1 (Ap1M in metamorphic rocks, Ap1V in volcanic rocks) and late-ore stage Ap2 (Ap2M, Ap2V). In situ U–Pb dating of Ap2M and Ap2V yields consistent ages of ∼150 Ma, indicating that metamorphic- and volcanic-hosted ores formed synchronously under a single Jurassic magmatic-hydrothermal system. Petrographic observations and trace element analyses of apatite and auriferous pyrite reveal that early-stage mineralization was dominated by magmatic-hydrothermal fluids, whereas late-stage mineralization experienced increasing influence from oxidizing meteoric water, accompanied by enhanced water–rock interaction. Fluid mixing and water–rock interaction are interpreted as key controls on gold precipitation. Compared to younger Cretaceous deposits in the SCVB, Wangmushan is temporally and genetically distinct, exhibiting unique orebody morphology, mineral assemblages, and alteration patterns. These findings not only highlight the complexity of Jurassic magmatic-hydrothermal evolution in southeastern China but also suggest that similar volcanic settings may host previously unrecognized gold deposits, providing important implications for regional exploration.