Source of metallogenic materials and ore-forming fluids,and metallogenic mechanism of the Yuanzhuding porphyry Cu-Mo deposit,western Guangdong Province,South China

The Yuanzhuding Cu-Mo porphyry deposit,located at the southwest of the Qin-Hang Neoproterozoic suture,is a newly discovered large-scale Cu-Mo deposit in the metallogenic belt.Based on a detailed analysis of geological characteristics and a study of H,O,S,and Pb isotopic geochemistry,the features of fluid evolution and the origin of the ore-forming fluid of the deposit has been discussed preliminarily in this paper.The results show that the sulfur came mainly from the ore-forming magma and theδ34 S values of sulfide in the ore distributed in a range between-4.3‰-3.9‰.The ore has a stable isotopic composition composed of common lead.Considering the Metallogenic geodynamics background,the Yuanzhuding deposit mineralization was closely related to a magmatic activity,and was originated from the mixing of the crust and mantle material triggered by the subduction.According to the alteration of H and O isotope composition in different ore-forming stage and the existing fluid inclusion studies, it is suggested that the mixing between meteoric water and the hydrothermal fluid of ore-bearing magma is the key factor that caused the Yuanzhuding metallic minerals precipitated out of the ore-forming fluids.