Abstract:The Liba gold deposit is located in the Liming ore cluster of west Qinling orogenic belt, occurs in the epi-metamorphic fine clastic rocks of the Devonian. It is produced in the thermal contact metamorphic belt outside the Zhongchuan intrusion and orebodies in the Liba gold field are controlled by the fracture zone. In detail, this paper analyzed the geological characteristics of the Liba gold deposit, the S isotopes of the host rocks, granite porphyry and ore sulfides by LA-MC-ICPMS and MAT-253 mass spectrometer. The Pb isotope of different geological bodies were measured by Nu Plasma HR MC-ICPMS. At the same time, the isotopic hydrogen and oxygen compositions of the ore-forming fluid was measured, and LA-ICP-MS zircon U-Pb dating was performed on granite porphyry dykes. The δ34S value of the pyrite ranges from 8.19‰ to 10.06‰ in granite porphyry, the host rocks δ34S value of the sulfides from 4.94‰ to 9.81‰. In contrast, the δ34S value of the ore sulfides from 4.94‰ to 10.82‰, close to the value of granite porphyry and host rocks represent the sulfur source is a mixture of formation rocks and magmatic hydrothermal. Zartman’s plumbotectonic model diagram shows that the data all fall near the orogenic and upper crust Pb evolutionary curve, and the ore lead coincide with the host rocks and dyke in Liba gold deposit. This indicates that a complex source of ore lead, which from the mixture of the host rocks and magmatism. The isotopic hydrogen and oxygen compositions supports a mixed origin of the ore-forming fluids, which compose of metamorphic, magmatic and formation water. Granitic porphyry and ore body are produced together, U-Pb age determination of zircon indicates that the granite porphyry intruded at 264.4±1.3 Ma, which is consistent with gold mineralization time, suggesting that mineralization and magmatic activities occur simultaneously. The Liba gold deposit and the magmatic rock are both the products of orogeny. The geological and isotopic geochemical characteristics of the deposit are similar to orogenic gold deposits. It shows that the Liba gold deposit is an orogenic gold deposit formed with a complex source of ore-forming materials under the environment from collision to extension in the Qinling orogenic belt.