Thermal, Compositional, and Rheological Structures of the Lithosphere Beneath the Changbaishan Volcanic Field and Their Controls on Volcanic Activity

Abstract The Changbaishan volcanic field (CVF), situated in the southeastern Central Asian Orogenic Belt, hosts a Cenozoic volcanic group including Changbaishan, Longgang, and Jingpohu volcanoes which exhibit distinct activities and surface rock compositions. To understand factors controlling these differences in eruptive activity and rock composition diversity, it is important to conduct integrated analysis of lithospheric thermal, compositional, and rheological structures. Here, we employ a probabilistic joint inversion incorporating surface heat flow, topography, geoid heights and Rayleigh wave phase and group velocity dispersion data to construct the thermal, compositional, and rheological structures of the lithosphere beneath the CVF. Joint inversion results indicate that lithospheric thickness beneath Changbaishan and Longgang volcanoes (∼55 km) is significantly thinner than that beneath Jingpohu volcano (∼85 km). In addition, a pronounced ∼200 km wide asthenospheric thermal anomaly exists beneath the Changbaishan volcano, while it is absent beneath Longgang and Jingpohu volcanoes. Crustal compositions beneath the Changbaishan volcano are dominated by felsic rocks, while they are restricted to the lower crust beneath Jingpohu. Rheological weakening (viscosity