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U-Pb systematics in small fractions of zircon, monazite, and sphene (5 to 20 grains each) have been analyzed in order to decipher the age and origin of magmatism in the Lhasa block and to date the tectono-metamorphic events. Additionally, we analyzed a few minerals for Rb-Sr. The results show that the granites and an ignimbrite were formed essentially through anatexis of continental crust, the magma source regions of which consisted of Palaeozoic to Precambrian materials up to 2 b.y. in age. The following episodes can be distinguished: (1) an early Tertiary plutonism-volcanism in the southern Lhasa block (Yangbajing region), strongly related to intracontinental tectono-metamorphism, (2) a late Jurassic to early Cretaceous plutonism in the central and northern Lhasa block, and (3) a middle Jurassic low-grade metamorphism, affecting the basement at the northern margin 171 ± 6 m.y. ago. The early Tertiary magmatism and metamorphism in the south are probably a direct result of Tethys subduction (Indian plate) underneath the southern Tibetan Plateau (Eurasian plate). In contrast, the plutonism in the north-e.g., the emplacement of the 121 ± 2 m.y. old granite at Bange and 120-140 m.y. old granite near Anduo-appears to be a result of intra-block thrustings resulting from the collision of the Lhasa block and the Qintang block (Bangong-Nujiang suture). This collision probably occurred in middle Jurassic (Bajocian) times as indicated by the low-grade metamorphism at the northern margin of the Lhasa block. Moreover, the existence of a $$531 ±_{14}^{13} m.y.$$ old granite gneiss in the northernmost part of the Lhasa block confirms that early Palaeozoic plutonism, well known from the Himalayas, was very extensive, affecting large portions of the pre-Gondwanian continent (Pangaea).