ABSTRACT

The Liaodong gold province, along the eastern margin of the North China craton, is a large productive base of gold in China. The Wulong gold deposit hosted in granitoid is a famous Au-bearing quartz vein gold deposit in this region, and located at the northern side of Sanguliu granite. The ages of Sanguliu granite determined by the conventional Rb-Sr isochron and U-Pb zircon methods are 131 ± 4.5 Ma and 129 ± 2.9 Ma respectively, thus the comprehensive isotopic age of Sanguliu granite is 130 Ma. Lode gold deposits commonly consist of pyrite and lesser amounts of galena and sphalerit sulfides accompanied by quartz and calcite. Here we use direct Rb-Sr dating of pyrite from Wulong gold deposit, and determined the age of Wulong gold deposit. A positive correlation between present-day ⁸⁷Sr/⁸⁶Sr and ⁸⁷Rr/⁸⁶Sr ratios of pyrite from the Wulong gold deposit corresponds to an age of 120 ± 3 Ma, which dates the age of gold mineralization. The Sr initial ratios (0.714816 to 0.7148927 of Sanguliu granite and 0.715280 to 0.715504 of pyrites in Au-bearing quartz veins) and Pb isotopic compositions in pyrites and Sanguliu granite indicates that lead was derived partially from the similar magmatic source, and the liner array of Pb isotope composition in pyrite show a incorporation of two end members (may be incorporation of basic and acid wall rocks). The studies of H and O isotopes of fluid inclusions in auriferous quartz veins demonstrate that the magmatic water predominates in ore fluids, and also reflect a little formation waters.