Abstract:The Baogutu gold deposit consists of quartz-vein type and alteration type ore bodies. The hydrothermal process can be divided into four stages: coarse-grained quartz vein stage (Ⅰ), gold-bearing fine-grained sulfide-quartz vein stage (Ⅱ), gold-bearing coarse-grained native arsenic -stibnite-quartz vein stage (Ⅲ) and calcite vein stage (Ⅲ). Gold mineralization occurred at stage Ⅱ and stage Ⅲ, forming native gold and electrum enclosed by or coexisting with quartz, pyrite, native arsenic and stibnite. The total REE content of quartz veins formed at stage Ⅰ and Ⅱ is 0.83×10-6~3.67×10-6 and 11.01×10-6~30.18×10-6, respectively. The fractionation between LREE and HREE in stage Ⅰ quartz vein[(La/Yb)N=8.53~21.89] is more obvious than that in stage Ⅱ quartz vein[(La/Yb)N=6.90~10.40], although they all show LREE-enriched chon- drite-normalized REE patterns which are similar to patterns of porphyries in Baogutu area, with slightly positive Eu anomaly and negative Ce anomaly. The chondrite-normalized REE patterns of sulfide samples such as pyrite and pyrrhotite separated from altered host rock and quartz veins are also right-oblique and characterized by obvious Eu negative anomaly (δEu=0.50~0.64). According to the Eu and Ce anomalies of quartz veins and pyrite, it can be concluded that the oxygen fugacity of the ore-forming fluid decreases from stage Ⅰ to Ⅱ. The Co/Ni ratios (1.60~10.50) of pyrite indicate that the ore-forming fluid is mesothermal, which is consistent with the estimation based on As atomic percentage in arsenopyrite. The gold-bearing quartz veins in the Baogutu gold deposit are closely related to intermediate-acidic stocks and veins in space and time, and they also share similar chondrite-normalized REE patterns and oxidation state, which indicates that the gold mineralization in Baogutu gold deposit is genetically related to intermediate-acidic magmatism in Baogutu area.