Ore-forming fluids and isotopic (H-O-C-S-Pb) characteristics of the Fujiashan-Longjiaoshan skarn W-Cu-(Mo) deposit in the Edong District of Hubei Province, China

•The Fujiashan-Longjiaoshan deposit is an oxided Cu-W-(Mo) skarn deposit.•The pristine ore-forming fluids and materials originated from magmatic rocks.•The fluid is high-T, high-salinity and high-fO2 NaCl-KCl-H2O system.•Meteoric water and organic matter are involved in the quartz-sulfide stage.•Cooling, meteoric water mixing, fluid boiling produced scheelite precipitation.