The Fluid Inclusions Study on Zhilingtou Molybdenum Deposit in Southwest Zhejiang Province

Since pyrite was found in the Zhilingtou deposit,Zhejiang Province in the mid-20th century,lead-zinc and gold-silver ore-bodies have been discovered as well.In recent years,a porphyry molybdenum deposit has been found beneath the goldsilver orebodies in Zhilingtou area.Molybdenum ore bodies mainly occur in the Badu Group in the outer contact zone of the granite porphyry.Similarly with the typical porphyry-type alteration zoning,the alteration types from molybdenum ore body to wall rock is from potassium-biotitization through beresitization to chloritization-carbonation.Ore fluids can be divided into early mineralization stage,the main mineralization stage,and the late mineralization stage.Fluid inclusions in the early mineralization stage are mainly Ia type ones with the homogenization temperatures from 354 to 442 ℃ and salinities from 12.3 to 19.4 wt% NaCl.Fluid inclusions in the mineralization stage include type Ⅱ and III.The homogenization temperatures of type Ⅱ range from 329 to 406 ℃ and the salinities vary between 3.5 and 6.2 wt% NaCl; the homogenization temperatures of type III range from 305 to 375 ℃ and the salinities vary between 30.6 and 45.8 wt% NaCl.Fluid inclusions in late mineralization stage belong to type Ⅰ b with the homogenization temperatures from 187 to 285 ℃ and the salinities from 3.5 to 8.4 wt% NaCl.Fluid boiling processes played an important role in metal precipitation of the Zhilingtou molybdenum deposit.The Raman spectra show that ore fluids are H2O-NaCl fluids.The hydrogen-oxygen isotopes data show that mineralizing fluids were magmatic fluids during the early and main mineralization stages and meteoric water was added in the late stage.