Mantle-derived fluids involved in large-scale gold mineralization, Jiaodong District, China: Constraints provided by the He-Ar and H-O isotopic systems

The Jiaodong super-large gold metallogenic region is located on the eastern margin of the North China craton and the western margin of the Circum-Pacific tectonic belt. Ore-forming chronology indicates that these deposits formed at 120 +/- 10 Ma. Helium and argon isotope compositions of fluid inclusions in pyrite range in He-3/He-4 ratios from 0.38 to 2.36 R/Ra (R: He-3/He-4 ratios of samples; Ra: He-3/He-4 ratios of Beijing air, 1.4 x 10(-6)) and in Ar-40/Ar-36 ratios from 310 to 1148. delta O-18 and delta D values of fluid inclusions in quartz are -2.16 to +6.28%. and -65 to -98%., respectively. A consistent relationship between H-O and He-Ar isotopic systems show that mantle-source fluids were involved in large-scale metallogeny in the Jiaodong region. The fluids were produced accompanying delamination, lithosphere thinning, and crust-mantle interaction that occurred in the eastern North China craton during the Early Cretaceous (140-120 Ma).