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The Tiegelongnan deposit is a newly discovered super-large porphyry-epithermal Cu-(Au) deposit in the western part of the Bangong Co-Nujiang metallogenic belt, Tibet(China). Field geology and geochronology indicate that the porphyry mineralization was closely related to the Early Cretaceous intermediate-felsic intrusions(ca. 123–120 Ma). Various epithermal ore and gangue mineral types were discovered in the middle-shallow part of the orebody, indicating the presence of epithermal mineralization at Tiegelongnan. Potassic, propylitic, phyllic and advanced argillic alteration zones were identified. ~(40)Ar/~(39)Ar dating of hydrothermal biotite(potassic zone), sericite(phyllic zone), and alunite(advanced argillic zone) in/around the ore-bearing granodiorite porphyry yielded 121.1±0.6 Ma(1σ), 120.8±0.7 Ma(1σ) and 117.9±1.6 Ma(1σ), respectively. Five hydrothermal mineralization stages were identified, of which the Stage IV pyrite was Rb-Sr dated to be 117.5±1.8 Ma(2σ), representing the end of epithermal mineralization. Field geology and geochronology suggest that both the epithermal and porphyry mineralization belong to the same magmatic-hydrothermal system. The Tiegelongnan super-large Cu-(Au) deposit may have undergone a prolonged magmatichydrothermal evolution, with the major mineralization event occurring at ca.120–117Ma.
The Tiegelongnan deposit is a newly discovered super-large porphyry-epithermal Cu- (Au) deposit in the western part of the Bangong Co-Nujiang metallogenic belt, Tibet (China). Field geology and geochronology indicate that the porphyry mineralization was closely related to the Early Cretaceous intermediate-felsic intrusions (ca. 123-120 Ma). Various epithermal ore and gangue mineral types were discovered in the middle-shallow part of the orebody, indicating the presence of epithermal mineralization at Tiegelongnan. Potassic, propylitic, phyllic and (40) Ar / ~ (39) Ar dating of hydrothermal biotite (potassic zone), sericite (phyllic zone), and alunite (advanced argillic zone) in / around the ore-bearing granodiorite porphyry 121.1 ± 0.6 Ma (1σ), 120.8 ± 0.7 Ma (1σ) and 117.9 ± 1.6 Ma (1σ), respectively. Five hydrothermal mineralization stages were identified, of which the Stage IV pyrite was Rb-Sr dated to be 117.5 ± 1.8 Ma (2σ), representin g the end of epithermal mineralization. Field geology and geochronology suggest that both both the epithermal and porphyry mineralization belong to the same magmatic-hydrothermal system. The Tiegelongnan super-large Cu- (Au) deposit may have undergone a prolonged magmatichydrothermal evolution, with the major mineralization event occurring at ca.120-117Ma.