Origins of ore-forming fluid and material of the quartz–vein type Mo deposits in the East Qinling–Dabie molybdenum belt: A case study of the Qianfanling Mo deposit

摘要: Abstract The Qianfanling quartz–vein type molybdenum deposit is located in the East Qinling–Dabie Mo belt. mineralization mainly present as structurally controlled Mo-bearing quartz veins. Based on chromatography analysis of deposit, gas compositions fluid inclusions dominantly contain H2O and relatively high concentrations CO2 (11.019 to 18.554 mol%). Cations anions liquid are Na+ Ca2 +, SO42 − Cl−, respectively. characteristics indicate that formed under conditions oxygen fugacity. Analytical results He-Ar isotopes pyrite from show 3He/4He ratios vary 0.02438 0.0796 Ra (Ra ratio air = 1.40 × 10− 6), with F4He values 252,509–885,224. calculated Hemantle range 0.18 0.87%, an average 0.39%. 40Ar/36Ar 694.4–1473.4, estimated 40Ar* (radiogenic 40Ar) proportion 79.9%. These isotopic data most He was derived crust, negligible atmospheric only a very small input mantle probably. Furthermore, Ar ore-forming crustal source, minor involved. 17 Re–Os model ages 15 molybdenite samples 4 quartz-vein deposits (Qianfanling, Daxigou, Maogou, Zhifang) 215.0 248.2 Ma, mean value 235.6 Ma, which close age peak collision between North China Yangtze Cratons. Re contents 0.19 39.16 ppm, 17.41 ppm, indicating crust-dominated source. Mesozoic different types belt ore sources. Combined inclusions, well this paper previous studies, we suggest material were magmatic This source could have by partial melting deep rocks certain condition during