Age of Ore Formation in the Ailinwudui Gold Deposit, Central Jilin, NE China: Geochronological Data and Metallogenic Insights

The Ailinwudui gold deposit is located in central Jilin Province and represents a newly discovered typical vein-type gold deposit hosted in a Paleozoic metamorphic rock series in recent years. At present, the metallogenic epoch and regional metallogenic tectonic setting of the deposit remain poorly constrained, which seriously restricts the understanding of gold metallogenic regularities and subsequent mineral exploration deployment in central Jilin. Previous studies indicate that the Ailinwudui gold deposit is a structurally controlled vein-type gold deposit. In this study, zircon U-Pb and muscovite 40Ar/39Ar geo-chronology were employed to precisely constrain the metallogenic timing of the gold mineralization. Zircon U-Pb dating yields an emplacement age of 174.7 ± 0.85 Ma for the granodiorite and a formation age of 209.5 ± 1.40 Ma for the rhyolite porphyry. Muscovite 40Ar/39Ar dating yields a plateau age of 180.39 ± 1.83 Ma, which confines the gold mineralization to the Early–Middle Jurassic. Whole-rock geochemical results reveal that the granitoids in the study area are enriched in large-ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in high-field-strength elements (HFSEs), showing typical arc-related magmatic affinities. The formation of this gold deposit is related to the subduction of the Paleo-Pacific Plate during the Early–Middle Jurassic. The research results can provide important geochronological and geochemical evidence for the study of gold metallogenic mechanisms and mineral exploration in central Jilin Province.