Two significant quartz-wolframite-veining mineralization events in the Jiangnan Orogen, South China: Constraints from in-situ U–Pb dating of wolframite in the Dongping and Dahutang W-(Cu-Mo) deposits

Abstract

The Jiangnan Orogen of South China is a world-class tungsten (W) metallogenic belt. Although the ore-forming ages of porphyry-skarn scheelite deposits in the Jiangnan Orogen are well quantified, the timing of quartz-vein type wolframite deposition is still ambiguous. Two typical quartz-vein type wolframite deposits, the Dongping and Dahutang deposits, were chosen for analysis. For the Dongping W deposit, a lower intercept 206Pb/238U age of 129.5 ± 5.4 Ma (1σ, MSWD = 0.75) was obtained for wolframite, which agrees well with the zircon weighted average mean 206Pb/238U age of 129.8 ± 0.3 Ma (2σ, MSWD = 0.4) from samples of the three granite units (biotite granite, muscovite granite and two-mica granite of the hidden pluton). This indicates that the quartz-wolframite-vein mineralization in the Dongping deposit has a genetic relationship with the hidden Dongping pluton. The wolframite samples from the Dahutang W deposit yielded a lower intercept 206Pb/238U age of 137.3 ± 4.8 Ma (1σ, MSWD = 1.9), which corresponds to previously reported scheelite Sm–Nd, molybdenite Re–Os and muscovite 40Ar–39Ar ages from the Dahutang deposit (142–138 Ma), as well as to monazite and zircon U–Pb ages for the ore-related biotite granite, biotite granite porphyry and granite porphyry (143–138 Ma). In combination with previous studies, these results constrain two significant quartz-wolframite veining events at ∼130 Ma and ∼140 Ma in the Jiangnan W metallogenic belt.