Abstract: The Kekesentao ophiolite outcrops in the south of the Erqis suture zone and tectonically mixed in the MidAltai;Kekesentao ophiolite;age;tectonic implicationsDevonian Yundoukala Formation. Main rocks of the ophiolite include serpentinized dunite, olivineAltai;Kekesentao ophiolite;age;tectonic implicationsgabbro and gabbro. In this study, we obtained zircon LAAltai;Kekesentao ophiolite;age;tectonic implicationsICPMS UAltai;Kekesentao ophiolite;age;tectonic implicationsPb age of the gabbros from this ophiolite. Zircons from western and eastern pluton yield concordant age of 332.1±1.5 Ma and 336.5±1.3 Ma respectively, indicating that both of them were coevally emplaced and the ophiolite was formed in early Carboniferous. Combining with the ages obtained in this study and the regional geology, we suggest that the Kekesentao ophiolite was the residue of the oceanic crust between the Kazakstan plate and the AltaiAltai;Kekesentao ophiolite;age;tectonic implicationsMongolia Terrane during their amalgamation at middle to late Carboniferous.