Geochemical characteristicss and genetic mechanism of the Buruocuo super-shallow granite body in Northern Tibet

Buruocuo granite consisted mostly of granite porphyry and rhyolitic cataclastlava has high silica,potassium,higher total alkalis,A/KNC value is greater than 1.10,and it's belongs to peraluminous granites.CaO/Na2 O ratio is greater than 0.3,and enrichment of the LILEs K,Rb,Ba,Th and REE,depletion of high field-strength elements Ta,Nb,Zr,Hf,coupled with slightly negative anomalies,moderate depletion of Eu-anomalies,which indicated that the post-collisional granite was formed by partial melting of the crust.Whole-rock K-Ar isotopic ages suggest that the Granites were formed at 94.8 Ma by intracontinental collision between the landmass of Qiangnan and Qiangbei in Late Jurassic to Early Cretaceous.The genetic mechanism is partial melting of deep crust and then the formation of magma,and the influx of upper crust of ultra-shallow granite emplacement environment along the fault.