Mineralization of the Daolundaba Cu-W-Sn deposit in the southern Great Xing'an Range: Constraints from zircon and monazite U-Pb and sericite 40Ar-39Ar ages

The medium-sized Daolundaba Cu-W-Sn deposit is located in the southern Great Xing'an Range. Orebodies in the deposit, including Cu, Sn, W, Cu-W, Cu-Sn, W-Sn, and Cu-W-Sn orebodies, occur as veins within the fractured zones of the Permian slate and Variscan biotite granite. The ore-forming process of the deposit can be divided into four stages: quartz-fluorite-muscovite-tourmaline-cassiterite-wolframite stage (stage I), quartz-fluorite-wolframite-chalcopyrite-arsenopyrite-pyrrhotite stage (stage II), quartz-fluorite-sericite-chalcopyrite-pyrrhotite-pyrite-silver mineral stage (stage III), and calcite-quartz-fluorite-pyrite stage (stage IV). LA-ICP-MS zircon U-Pb age of the fine-grained granite from the Zhangjiayingzi intrusion occurring in the periphery of the deposit is 136.1 +/- 0.4Ma. LA-ICP-MS monazite U-Pb ages for two samples from Cu-W orebodies of the stage II and one sample from Cu orebodies of the stage III are 136.0 +/- 2.3Ma similar to 135.1 +/- 2.2Ma and 134.7 +/- 2.8Ma, respectively. 40Ar-(39) Ar dating for one sericite sample from Cu orebodies of stage III yielded a plateau age of 138.8 +/- 0.47Ma and an isochron age of 140.0 +/- 1.1Ma. The dating results show that the Cu-W and Cu orebodies in the Daolundaba deposit all formed during the Early Cretaceous and belong to the same metallogenic system. The mineralization of the Daolundaba deposit is closely related to Early Cretaceous highly fractionated granite.