Ages, H–O–C–S–Pb isotopes, and fluid inclusion study of the Daolundaba Cu–Sn–W–Ag deposit in Inner Mongolia, NE China

•The dating of monazite and sericite indicates that the Daolundaba deposit formed at 135–140 Ma.•The deposit is a magmatic hydrothermal deposit with moderate–high temperature and high salinity.•The ore-forming fluids of the deposit consist mainly of magmatic water with an H2O–NaCl–CO2–CH4 affinity in composition.•The ore-forming materials of the deposit mainly came from the Early Cretaceous magma.•The multi-stage fluid boiling and mixing were the two dominant mechanisms for the precipitation of materials.