For a century, the Himalaya–Tibet orogen has been explained as a simple doubling of crustal thickness during the India–Asia collision. Yet such a model is at odds with experimental, geophysical, and geochemical constraints. Crust thicker than ~40 km is too weak to sustain the plateau over tens of millions of years, and mantle rocks exhumed in southern Tibet point to mantle material at depths where a thickened crust should lie. In our study, fully coupled geodynamic models instead show that the architecture of the orogen is better explained by viscous underplating of Indian crust beneath Asian lithosphere. In this configuration, buoyant Indian crust and rigid Asian mantle together support the Himalaya–Tibet system.
I became involved in the project through earlier collaboration with Simone P. and Rhodri Davies on a Nature Geoscience paper, where I applied thermodynamic modeling to translate geodynamic outputs into seismic velocities. Here, I used the same approach: converting the modeled pressure–temperature fields into shear-wave velocity structures and applying seismic filtering to ask whether current geophysical methods could resolve the predicted intra-crustal mantle layer.
The results show that while the models consistently produce an interlayer of mantle lithosphere between Indian and Asian crust, this feature is difficult to detect in seismic data because it is blurred by resolution limits. Nevertheless, its presence explains the persistence of Tibet’s elevation and reconciles geophysical observations with petrological evidence. In this way, the work reframes a century-old view of Himalayan mountain building and highlights the importance of bridging geodynamic modeling, mineral physics, and seismology.