Evidence of zircon U-Pb geochronology for magma mixing of Xiaerpu granite in West Junggar

Although petrographical is the most direct and the most important evidence of identifying magma mixing, but the accurate isotopic ages of the host rock, enclave from mantle source, and basic dyke swarm are vital complementarity. Xiaerpu granite are composed of the host rock, mafic microgranular enclave, and basic dyke swarm, LA-ICP-MS zircon U-Pb dating of the three indicates that the weighted mean Pb-206/U-238 age of them are 297. 6 +/- 2. 5Ma, 298.2 +/- 8. 0Ma, 298.9 +/- 5. 0Ma, that is same in error range, which show their formed in the same magma intrusion event, providing chronological proof for magma mixing of Xiaerpu granite. The establishment of magma mixing of Xiaerpu granite proving that crust depth of West Junggar has had the intense magma mixing action in Early Permian, standing for a important events of growth of the continental crust in West Junggar, and Xiaerpu granite' s mafic microgranular enclave and basic dyke swarm are the matter recorder of this growth event.