Using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), U-Pb dating and in-situ trace element analysis were performed on magmatic zircons from monzogranite porphyry and quartz porphyry in the Wunugetushan mining area, Inner Mongolia, to constrain the nature of the ore-forming magma and explore the main controlling factors of porphyry mineralization. The results show that the zircon U-Pb age of the monzogranite porphyry is 180.9±0.67 Ma, consistent with the previously reported molybdenite Re-Os age (≈180 Ma); the zircon U-Pb age of the quartz porphyry is 202.6±1.4 Ma, indicating that it is a pre-mineralization intrusion. Zircons from the syn-mineralization monzogranite porphyry exhibit significant positive Ce and Eu anomalies and high oxygen fugacity (ƒ_O2 is from −14.6 to −12.9, ΔFMQ is from +2.3 to +3.5), whereas zircons from the barren quartz porphyry show lower Ce and Eu anomalies and lower oxygen fugacity (ƒ_O2 is from −17.1 to −9.8, ΔFMQ is from −0.5 to +2.0). Both monzogranite porphyry and quartz porphyry zircons display high 10000×δEu/Y ratios and low Dy/Yb ratios, reflecting similar magmatic water contents. The zircon geochemical characteristics indicate that the primary magma of the ore-bearing monzogranite porphyry is characterized by high oxygen fugacity and water richness, whereas the primary magma of the barren quartz porphyry has relatively high water content but low oxygen fugacity, revealing the critical control of magmatic oxygen fugacity on porphyry mineralization potential. In the context of regional tectonic evolution, the Early Jurassic syn-mineralization period of the Wunugetushan deposit was likely influenced by the subduction of the Mongol-Okhotsk Ocean, with resulting partial melting generating the high oxygen fugacity, water-rich magma essential for mineralization. 

利用激光剥蚀–电感耦合等离子体质谱(LA-ICP-MS)方法, 对内蒙古乌努格吐山矿区二长花岗斑岩和石英斑岩中岩浆锆石进行U-Pb 定年和原位微量元素分析, 厘定成矿岩浆性质, 探讨斑岩成矿的主控因素。结果表明, 研究区二长花岗斑岩锆石U-Pb年龄为180.9±0.67 Ma, 与前人报道的辉钼矿Re-Os年龄(≈180 Ma)一致; 石英斑岩锆石U-Pb年龄为202.6±1.4 Ma, 属成矿前岩体。成矿期二长花岗斑岩锆石具Ce和Eu显著正异常和高氧逸度值(ƒ_O2 = −14.6 ~ −12.9, ΔFMQ = +2.3 ~ +3.5)特征, 不成矿的石英斑岩Ce 和Eu异常值以及氧逸度值(ƒ_O2 = −17.1 ~ −9.8, ΔFMQ = −0.5 ~ +2.0)较小。二长花岗斑岩和石英斑岩锆石均显示较高的10000×δEu/Y 值和低Dy/Yb值, 反映二者相似的岩浆水含量。锆石地球化学特征表明, 研究区成矿二长花岗斑岩的初始岩浆具有高氧逸度且富水的特性, 不成矿石英斑岩的初始岩浆水含量相对较高且氧逸度低, 揭示了岩浆氧逸度对斑岩成矿潜力的关键性控制作用。结合区域大地构造演化, 乌努格吐山矿床成矿期的早侏罗世可能受蒙古–鄂霍茨克洋俯冲作用影响, 所触发的部分熔融形成成矿必需的高氧逸度且富水的岩浆。