Spatial Distribution of Igneous Rocks in the Tibetan Plateau

The Tibetan Plateau contains abundant igneous rocks of varying kind, including ultramafic, mafic, intermediate and felsic volcanic and intrusive rocks of Paleozoic to Cenozoic age, which record the origin and evolution of the Tibetan Plateau since the Paleozoic. They are distributing in five giant magmatic belts from the north to south as follows: Qinling-Qilian-Kunlun giant magmatic belt (QQKB), Qiangtang giant magmatic belt (QTB), Gangdese giant magmatic belt (GDB), Himalaya giant magmatic belt (HMLB) and Sanjiang giant magmatic belt (SJB). Magmatic rocks in west Qinling formed during late Permian to early middle Triassic, and late Triassic to early Jurassic epochs, associated with seafloor subduction and continental collision. The Qilian magmatic belt contains ocean ridge basalts and oceanic island basalts of early Cambrian to early Ordovician age, arc volcanic rocks and granitoids association and back arc basin magmatic association of the Ordovician age with locally para-aluminum granite and A-type granite association of late Silurian to Devonian age. The Kunlun magmatic belt widely developed vast intrusive (mainly granitoids) and some volcanic rocks from Precambrian, through early Paleozoic (Caledonian), late Paleozoic to early Mesozoic (Hercynian to Indosinian), late Mesozoic (Yanshanian) to Cenozoic (Himalaya) epoch. In Qiangtang area volcanic rocks formed mainly in Cenozoic epoch, forming the largest Cenozoic volcanic belt, while intrusive rocks developed mainly in the southern Qiangtang, including late Paleozoic mafic rocks and late Mesozoic granite-granodiorite-diorite and some sporadic Cenozoic porphyry, ultramafic rocks and diabase dikes. In Himalaya area, the main intrusive rock granitoids with pale color distribute in the High Himalayan Belt and Northern Himalayan Belt during the Proterozoic, Ordovician and Miocene epoch and also a large number of volcanic interbeds dominated by basalts of varying ages are found in the Himalayan Belt. The Sanjiang region developed vast intrusive and volcanic rocks with complicated lithologies forming several magmatic belts, which contain important information of the history and evolution of pre-Paleo-Tethys, the Paleo-Tethys, the Neo-Tethys and Indo-Eurasian collision.