LA-ICP-MS zircon U-Pb ages of the volcanoic rocks from the Chaotugou Formation in Aohan Banner, Inner Mongolia

LA-ICP-MS zircon U-Pb dating of the metavolcanic rocks from the Chaotugou Formation in Chifeng-Aohan Banner area of Inner Mongolia was carried out in this paper. The study area is located on the north margin of the North China Craton tectonically. The volcanic rocks of the Chaotugou Formation consist of basalts and rhyolites. LA-ICP-MS zircon U-Pb dating of rhyolite yielded U-Pb ages of between 359.4±1.4Ma and 360.3±1.4Ma, representing the time of crystallization of the volcanic rocks. The dating result reveals that the rhyolite from the Chaotugou Formation was formed in Late Devonian rather than in Early Carboniferous as previously thought. The Late Devonian volcanic rocks are basalts and rhyolites, suggesting a typical bimodal volcanic rock association and implying an extensional environment.