The Tiegelongnan Cu (Au, Ag) deposit in central Tibet contains more than 10×10⁶ t of copper ranking 29^th in the world. It is characterized by typical porphyry-epithermal alteration and mineralization. In order to improve the understanding of porphyry-epithermal copper deposit in Tibet, new zircon U-Pb age and sulfur isotope data along with published data in the Tiegelongnan are presented to investigate the formation and preservation mechanism. Ore-related intrusive rocks in the Tiegelongnan including Early Cretaceous (about 120 Ma) granodiorite porphyry and diorite porphyry are closely related to the northward subduction of Bangongco-Nujiang ocean. Sulfur mainly comes from deep magma, and ore-forming fluid is affected by both magmatic and meteoric water. The metallogenic setting of Tiegelongnan is consistent with those of Andean porphyry copper deposits in South America. The cover of the Meiriqiecuo Formation volcanic rocks, Lhasa-Qiangtang collision and India-Eurasian collision have significance in the preservation and uplift of the deposit. The formation, preservation and discovery of Tiegelongnan play an important role in exploration of ancient porphyry-epithermal deposits in Tibet.

This paper presents new apatite fission track (AFT) and apatite (U-Th)/He (AHe) data from the Duolong ore district. The corresponding AFT and AHe ages provide insights into the uplift and exhumation history of the Duolong ore district, revealing rapid exhumation with an erosional exhumation rate of 0.067 km/Ma between 65 and 35 Ma, and slow exhumation with an erosional exhumation rate of 0.023 km/Ma since 35 Ma. The new data in this study, along with previous low-temperature thermochronology data, show that samples with ages from 130 to 83 Ma are distributed close to Shuanghu in the central Qiangtang, samples with ages from 65 to 45 Ma are distributed evenly across the whole Qiangtang terrane, and several samples with ages from 20 to 7 Ma are distributed at the edge of the Qiangtang terrane. The Qiangtang terrane experienced heterogeneous surface uplift. The central Qiangtang was initially uplifted during the Early Cretaceous, and the weathered paleosoil dated between 120 and 110 Ma in the Duolong ore district is consistent with the exhumation during this period. Large-scale uplift and exhumation of the Qiangtang terrane between the Palaeocene and Eocene is consistent with the rapid exhumation of the Duolong ore district between 65 and 35 Ma; finally, the uplift and exhumation at the edge of the Qiangtang terrane since the Eocene caused the Duolong ore district to be uplifted to its present elevation.

The Duolong porphyry copper–gold district, located in the northwestern segment of the Bangongco–Nujiang metallogenic belt on the southern margin of the South Qiangtang terrane (Tibet), hosts typical porphyry-style Cu-Au mineralization with well-defined alteration zoning from potassic through chlorite–sericite to propylitic assemblages. Based on integrated in situ major/trace element and sulfur isotope analyses of pyrite and chalcopyrite from different alteration zones, we identify two discrete episodes of magmatic-hydrothermal activity that exerted distinct controls on metal endowment. Sulfur isotope signatures define a systematic evolution from the earliest, high-temperature potassic stage (δ³⁴S: Py-I −3.70 to −1.16‰, mean −2.14‰; Cp-I −4.92 to −0.90‰, mean −2.54‰) through propylitic alteration (Py-II: 1.20‰–5.16‰, mean 3.06‰) to the later chlorite–sericite stage (Py-III: −2.00 to 1.86‰, mean 0.06‰; Cp-II: −2.50 to 0.58‰, mean −0.77‰), tracking progressive fluid cooling and changing fluid sources. Trace element systematics further discriminate these episodes: sulfides from potassic and chlorite–sericite zones are enriched in trace elements, whereas propylitic pyrite is depleted, with potassic pyrite recording the highest Cu concentrations (559–7256 ppm, mean 2302 ppm) and chlorite–sericite pyrite containing the lowest Au contents (0.01–0.59 ppm, mean 0.10 ppm). Gold mineralization occurs as native gold exsolved from chalcopyrite, and the markedly low Au concentrations in chlorite–sericite pyrite (0.01–0.59 ppm, mean 0.10 ppm) demonstrate that gold exsolution was largely completed during the first, high-temperature magmatic-hydrothermal stage. Collectively, these results establish a detailed geochemical framework linking sulfide composition to specific hydrothermal stages, providing new constraints on the processes of porphyry copper–gold mineralization in a collisional setting.