Fluid inclusion and stable isotope constraints on the genesis of the world-class Zhuxi W(Cu) skarn deposit in South China

•Fluids in the three skarn stages are characterized by complex volatile system, respectively.•Isotopic data showed a primary magmatic source, mingled with meteoric water at the late stages.•Boiling, temperature falling and fO2 rising are the key to metal deposition at the retrograde stage.•fO2 and temperature decreasing play role in metal precipitation at the late hydrothermal stage.