Spatial and temporal distribution of peraluminous granites in Tibet and their tectonic significance

The distribution of peraluminous granites in Tibet is treated on the basis of the tectonic zones in which they occur, their spatial and temporal distribution, the peak of magmatic activity and the volume of magma intruded. Magmatic activity, with the intrusion of peraluminous granites, was initiated during the Early Jurassic and culminated in the middle Miocene, especially between 20 and 10 Ma. Rock types include tourmaline, muscovite and two-mica granites. Magmatic activity in the Gangdise Belt migrated from the east to west and from the south to the north. Episodes of tectonic evolution for the lithosphere of the Qinghai–Xizang (Tibet) Plateau, deduced from peraluminous granite intrusion are: (1) Latest Triassic to Early Jurassic (208–157 Ma), representing the subduction phase of the Bangong Co–Nu Jiang oceanic zone; (2) Late Jurassic to Early Cretaceous (157–97 Ma), representing the subduction and collision phases of the Bangong–Nu Jiang oceanic zone; (3) Late Cretaceous to early Paleocene (97–65 Ma), representing the subduction and initial collision phases of the Yarlung Zangbo oceanic zone ; (4) Paleocene to Eocene (65–40 Ma), representing the major collisional stage of the Yarlung Zangbo Oceanic zone and the formation of crust-derived granites; and (5) Oligocene to Recent, representing an intense intracontinental convergence phase.