Petrogenesis and tectonic implications of the Triassic rhyolites in the East Kunlun Orogenic Belt, northern Tibetan Plateau

The East Kunlun Orogenic Belt (EKOB), which is in the northern part of Greater Tibetan Plateau, contains voluminous Late Triassic intermediate-felsic volcanic rocks. In east end EKOB, we identified highly differentiated peralkaline-like Xiangride rhyolites (~209 Ma) that differ from widespread andesitic-rhyolitic Elashan volcanics (~232–225 terms their field occurrences and mineral assemblages. older, more common calc-alkaline felsic may have originated partial melting underthrust Paleo-Tethys oceanic crust under amphibolite facies conditions associated with continental collision. syn-collisional granitoids EKOB are different products same magmatic event related to characterized by elevated abundances high strength elements, especially very Nb Ta contents, low Ba, Sr, Eu, P, Ti contents; variably 87Sr/86Sr ratios (up 0.96), exhibiting remarkable similarities characteristic peralkaline rhyolites. primitive magmas parental were most likely alkali basaltic underwent protracted fractional crystallization contamination. rock associations early rocks late alkaline dikes provide important information about tectonic evolution post-collisional. We infer transition collisional compression post-collisional extension occurred at 220 Ma.