Abstract: Many dikes occur along the Xinjiang-Tibet Highway in the western segment of the West Kunlun. Those exposed in the field are lamprophyre, diabase, diorite and granite dikes. Whole-rock K-Ar dating of these dikes indicates that their emplacement ages may well correspond with tectonic events in the study area. The 273-280 Ma age of emplacement of diabase dikes corresponds with the timing of back-arc spreading and the 230-244 Ma age of emplacement of diorite and granite dikes corresponds with the timing of collisional orogeny.