Zircons of gold ores in hydrothermal quartz vein type deposit can be derived from wall rocks or hydrothermal activities. Therefore,it is helpful to reveal the information of diagenesis and mineralization.The Zhongshangou gold deposit is located in Zhangjiakou—Xuanhua (Zhangxuan) area,Hebei Province,which occurs in the western part of Shuiquangou granite in the form of quartz vein type and is one of the typical gold deposits in the core of Zhangxuan mantle branch structure.This paper takes zircons in gold-bearing quartz veins of the Zhongshangou gold deposit as the research object.Methods:Based on the geological characteristics of the orefield,LA-ICP-MS U-Pb isotopic dating and Hf isotopic characteristics of zircons in gold-bearing quartz veins have been mainly studied.Results:It is found that the zircons mainly show characteristics of magmatic zircon,with idiomorphic—hypidiomorphic texture and oscillatory zones,an average of 0.97 in Th/U ratio.The REE content of zircons is 351×10-6 ~976×10-6,with an average value of 690×10-6,which has obvious LREE depletion and HREE enrichment characteristics.The normalized curve of REE in the chondrite generally presents a left inclined type with the same slope. Two group very consistent U- Pb ages of a concordant age of 391 ± 1 Ma and a weighted average age of 391± 3 Ma have been obtained from 17 zircon U-Pb dating data,indicating crystallization age of magmatic zircons from gold-bearing quartz veins.From 11 Hf isotopic data,the values of εHf(t) range from-21.4 to -16.6,the values of TDM1range from 1.7 Ga to 1.9 Ga with an average of 1.7 Ga,and the values of TDM2are mainly concentrated in 2.4~2.6 Ga,with an average of 2.5 Ga.In the Hf isotope evolution diagram,the data points are located under the depleted mantle and chondrite evolution line and nearly 2.5 Ga ancient crust evolution line,reflecting the average age of the source material in the crust.Conclusions: Combined with the regional geology,orefield geology and zircon characteristics,it shows that the oreforming age of Zhongshangou gold deposit is not earlier than 391 ±1 Ma,inferring that it may have been formed in the Early Hercynian period,with hydrothermal superimposed mineralization in the Yanshanian period.The main diagenetic age of Shuiquangou granite is from late Caledonian period to Early Hercynian period.