The Tibetan Plateau is one of the regions in China where igneous rocks are very widely developed. Various types of
volcanic and plutonic rocks are distributed over 300,000 km2 in area and take 10% area of the entire Plateau. These igneous rocks
and carried deep-seated nodules play important roles in understanding geodynamic evolution of the Tibetan Plateau, as either
lithoprobes/windows or tectonic records, and are closely related to mineralization as well. This paper discusses some important
scientific topics via studying igneous rocks. (1) The timing of Indo-Asia collision: This is a very important scientific problem.
There is, however, a wide range of discrepancy about the timing of initiation of the collision (from earlier than 70 Ma, to even
later than 34 Ma). According to multiple lines of evidences from the 1500 km-extending main collision zone in southern Tibet, we
deduced a conclusion that Indo-Asia collision likely started from 65/70 Ma and completed in c. 40 Ma (syn-collisional stage), and
then transformed into post-collisional stage after 40 Ma. (2) Underplating and magma mixing, an event of mantle-crust interaction
during syn-collisional stage: There are abundant evidences for underplating and magma mixing in southern Gangdese. An
important process of continental growth and evolution took place in the Tibetan Plateau. (3) The origin of formation of extremely
thick crust of the Tibetan Plateau: A deduction of “Two types of crust and two types of mechanism” is suggested based on the
studies of collisional and post-collisional igneous rocks. There are two types of crust, juvenile crust and recycled crust, in the
Plateau. Crustal thickening of the Plateau was caused by two types of mechanism, i.e., both structural compression and input of
mantle materials via magmatism. (4) The composition, structure and evolution of the lithosphere of the Tibetan Plateau: There are
three geochemical reservoirs in the lithospheric mantle, and three types of lithospheric structure underneath the Tibetan Plateau.
Nodules and outcrops of mantle/lower crust-seated rocks are found in several locations of the Plateau. (5) Possible lateral flow of
lower crust and upper mantle: Migration of collisional and post-collisional volcanism with time shows a highly distinctive pattern,
which can be interpreted to reflect lateral flow of the lower crust and asthenospheric mantle induced by the approach and ensuing
collision of relatively thick (India and Eurasia) continental plates.