Petrogenesis, Diagenesis and Mineralization Ages of Galale Cu-Au Deposit,Tibet: Zircon U-Pb Age, Hf Isotopic Composition and Molybdenite Re-Os Dating
Zhang Zhi
Song Junlong
Tang Juxing
Wang Liqiang
Yao Xiaofeng
Li Zhijun
Abstract：The Gelale Cu-Au deposit in Tibet is an example to probe the regional tectonics, but its ore-forming age is poorly studied, which hinders further studies for the regional tectonics, magmatism and mineralization in the metallogenic belt.The ages and genesis of the intrusive rocks, and the ages of the deposit are determined for the first time in this paper by using the laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS) zircon U-Pb dating, Lu-Hf isotopic test and Re-Os isotopic dating methods.Early diorite yields age of 155.8±2.3Ma and εHf(t) values of-14.68~-8.34 (-11.74 in average), which is the product of the southward subduction of the Bangong-Nujiang Tethys ocean.The age of the inter-mineral granodiorite is 88±1Ma(MSWD=0.56,n=21),and yields zircon εHf(t) values between 5.84-9.20, with the average value of 7.72, while the ages of the late granite porphyry is 84.67±0.8Ma(MSWD=1.9,n=18),and yields zircon εHf(t) values between 6.32-9.78, with the average value of 8.40.Both the granodiorite and granite porphyry emplaced in the Late Cretaceous, which is the product of the convergence of the Lhasa terrane and the Qiangtang terrane.The Re-Os isochron age of molybdenite in the district is 88.55±0.60Ma (MSWD=0.60,n=8), which is close to the age of the mineralization rock (granodiorite).Comprehensive study shows that the magmatic activities of the deposit corresponed to the subduction and collision environment of the Bangong-Nujiang Tethys ocean, and the Galale copper-gold deposit is the product of the mineralization event of the collision stage.
Keywords：magmatic activitymetallogenesissubductioncollisionGalalepetrology
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：19( 862-880 )