The Role of Jiningian Pluton in Yanshanian Metallogenic Events in the Dahutang Tungsten Deposit: Evidence from Whole Rock and Zircon Geochemistry

Abstract

The Dahutang tungsten deposit is one of the largest deposits in the Jiangnan tungsten belt. The Jiningian pluton is widely distributed in the orefield, which is considered an ore-bearing wall rock and Ca source for scheelite mineralization. The Jiningian granodiorite samples near ore have high W contents (average 93 ppm). Moreover, their SiO2 and P2O5 contents are positively correlated in Harker diagrams, and the A/CNK values vary between 1.18–1.71, suggesting that the Jiningian granodiorite is high fractionated S-type granites and has the potential for W mineralization. The zircon U-Pb ages of the Jiningian granodiorite samples (17SWD-1, 17SWD-2) are 845 ± 21 Ma (MSWD = 1.7) and 828.7 ± 7.5 Ma (MSWD = 1.0), respectively, representing the formation ages of the Jiningian pluton. The U-Pb age of hydrothermal zircons (~140 Ma) in the Jiningian granodiorite samples is consistent with the mineralization age (150–139 Ma), indicating the strong superimposed modification of the Yanshanian mineralizing fluids. The positive correlation between Ca and W molarity in the Jiningian granodiorite samples demonstrates that they provide considerable Ca and W during Yanshanian mineralization. The W activation migration due to sodium alteration can be inferred from the inverse correlation between Na and W molarity. The study tries to provide a new perspective on the origin of mineralized material in the world-class Dahutang tungsten deposit.