Thermal History of the Naruo Porphyry Deposit in the Duolong Ore District, Western Tibet: Evidence from U‐Pb, 40Ar/39Ar and (U‐Th)/He Thermochronology

AbstractThe Naruo porphyry copper deposit containing more than 2 Mt of copper is located in the Duolong ore district in the west of the Bangongco–Nujiang belt in central Tibet. New zircon U‐Pb, biotite 40Ar/39Ar, zircon (U‐Th)/He ages, published age data together with thermal modeling were presented in this paper to investigate the thermal history of Naruo deposit. Thermal modeling reveals a prolonged magmatic‐hydrothermal evolution firstly cooling from ∼700°C to ∼350°C at 120 Ma, then cooling to 230°C at 106 Ma and maintaining at 200°C from 106 to 90 Ma which is attributed to multiple magmatic events and thermal effect of strike‐slip fault. Affected by thrust nappe structure, the sample was consistent with 120°C from 70 to 63 Ma. The Naruo deposit started to experience exhumation at a rate of ∼0.07 km/Myr since 60 Ma which is related to India‐Asia collision. The prolonged magmatic‐hydrothermal evolution process might have important influence on the Naruo deposit. The ore‐related intrusions preserved in the foot walls of strike‐slip fault and thrust nappe structure are the objects of future exploration in the Duolong ore district.