Abstract: The meta-basic plutons are extensively developed within the Paleoproterozoic monzogranitic gneiss in the eastern most Quanji massif; however, their formation and metamorphic ages and implications for the basement tectonic evolution remain unclear. In this paper, the zircon U-Pb age of one of the meta-basic plutons was determined with LA-ICP-MS. Ten analytical data show strong lead loss due to thermal events, but their discordant line remains well correlated with the upper intercept age of 1712±47 Ma and lower intercept age of 472±29 Ma, MSWD=1.4. The dating result indicates that the protolith of this pluton was formed in the early Mesoproterozoic, being the product of the initial break-up process after the assembly of the Quanji massif with the supercontinent Columbia in the Late Paleoproterozoic. The proton then underwent amphibolite facies metamorphism and structural dismantling resulting from its being involved into the North Qaidam Collision Zone in the Early Paleozoic.