Tibetan Plateau insights into >1100 °C crustal melting in the Quaternary

Abstract Partial melting during high-temperature to ultrahigh-temperature (UHT) metamorphism facilitates crustal differentiation, element transfer, and the evolution of topography in orogens, however mechanisms that drive heating Earth’s crust remain controversial. We provide new evidence from ca. 2.3 Ma dacites Tibetan Plateau, representing youngest known UHT metamorphic event. Our results show these were mainly generated by fluid-absent metasedimentary rocks minor mafic at peak temperatures 1100–1150 °C pressures 0.8–0.9 GPa. The represent mixtures melts granulite residues are geochemically similar A-type granites with extremely high heat-production values (5.33–5.99 μW m–3). Compared geological geophysical observations, numerical modeling indicates key factor determining thermal Tibet is thickness radioactive layer. Orogens dominated felsic composition, like Tibet, could easily reach conditions within a short period time (20–40 m.y.) after thickening heating, without need for an additional tectonic mechanism.