The evolution of the magmatic-hydrothermal system that formed the Triassic Erdenetiin Ovoo porphyry Cu-Mo deposit, northern Mongolia, is reconstructed through the study of the sequence of stockwork veining and the petrographic characteristics of the veins, as well as the cathodoluminescence and fluid inclusion characteristics of the vein quartz. Early A veins associated with potassic alteration formed at temperatures ≳ 500 °C under lithostatic pressures. The quartz in these veins shows a blue cathodoluminescence emission and is extensively recrystallized. Subhedral to euhedral quartz crystals contained in AB veins precipitated at the ductile to brittle transition at ~ 400–450 °C. The quartz crystals have cores showing a long-lived purple cathodoluminescence color with well-developed growth zoning, whereas the rims of the crystals lack growth banding and have a brownish-red cathodoluminescence emission. Fluid inclusions in the A and AB veins show elevated CO₂ concentrations but show no evidence for immiscibility, implying that Erdenetiin Ovoo formed at ≳ 5 km below paleosurface. Quartz in the A and AB veins is crosscut by molybdenite ribbons. The presence of encapsulated molybdenite and sericite grains along growth zones in the quartz rims of the subhedral to euhedral quartz crystals constrains the timing of Mo introduction and suggests an association with the sericite alteration of the host rocks, which affected 50–60% of the deposit. Elevated Cu grades at Erdenetiin Ovoo are linked to the occurrence of C veins, which consist primarily of chalcopyrite and pyrite. These veins surrounded by halos of sericite-chlorite alteration lack quartz as a gangue mineral, suggesting formation at conditions of retrograde quartz solubility at ~ 400 °C and hydrostatic pressures. Late D veins formed at ≲ 375 °C and hydrostatic conditions. The veins consist primarily of pyrite and are associated with texturally destructive sericite alteration of the host rocks. The study demonstrates that hypogene Cu mineralization at Erdenetiin Ovoo was predated and post-dated by sericite alteration, which has important implications to alteration vectoring in porphyry exploration worldwide.

通过对网脉脉序、脉岩学特征、阴极发光和流体包裹体的研究，重建了蒙古北部三叠纪额尔登亭敖包斑岩铜钼矿床的岩浆热液系统的演化过程。脉石英的特征。与钾蚀变相关的早期 A 矿脉在静岩压力下温度≳ 500 °C 时形成。这些矿脉中的石英发出蓝色阴极发光，并且发生了广泛的再结晶。 AB 脉中含有的次面体到自面体石英晶体在约 400–450 °C 的延性到脆性转变时沉淀。石英晶体的核心显示出长寿命的紫色阴极发光颜色，具有发达的生长带，而晶体的边缘缺乏生长带并具有棕红色阴极发光发射。 A 和 AB 矿脉中的流体包裹体显示出较高的 CO ₂浓度，但没有显示出不混溶的证据，这意味着额尔登敖包形成于古地表以下 ≳ 5 km 处。 A 和 AB 矿脉中的石英被辉钼矿带横切。沿着亚面体到自形石英晶体的石英边缘的生长区存在封装的辉钼矿和绢云母颗粒，限制了钼引入的时间，并表明与母岩的绢云母蚀变有关，后者影响了 50-60% 的矿床。额尔登敖包的铜品位升高与 C 矿脉的出现有关，C 矿脉主要由黄铜矿和黄铁矿组成。这些被绢云母-绿泥石蚀变晕圈包围的矿脉缺乏作为脉石矿物的石英，表明在约 400 °C 和静水压力的逆行石英溶解度条件下形成。晚 D 脉在 ≲ 375 °C 和静水条件下形成。这些矿脉主要由黄铁矿组成，与主岩的结构破坏性绢云母蚀变有关。研究表明，额尔登敖包的深近系铜矿化早于和晚于绢云母蚀变，这对全球斑岩勘探的蚀变矢量具有重要意义。