A new study published in
Tectonics reveals that the Earth's crust beneath the Himalayas is not simply doubled, as had been believed for a century. Researchers used computer simulations to model the collision between the Indian and Eurasian plates. They discovered that the mantle, a denser layer located beneath the crust, plays a role in the stability of the mountain range.
The Himalayan range, with Mount Everest, formed during the collision of the Asian and Indian continents.
Illustration image Pixabay
According to the old theory of Émile Argand, the crust had piled up to a thickness of 70 to 80 kilometers (about 43 to 50 miles). However, the extreme temperatures at that depth make the rocks ductile, similar to yogurt, unable to support the weight of the mountains. This mechanical weakness pushed scientists to reconsider the model.
Pietro Sternai's team identified a rigid mantle layer inserted between the two crusts. This sandwich structure provides the necessary strength to support the Himalayas and the Tibetan Plateau. The denser mantle does not melt as easily as the crust, offering a solid foundation.
The simulations were corroborated by seismic data and rock analysis. Simone Pilia, co-author of the study, explains that this new model solves persistent geological puzzles. For example, it justifies why some observations did not match the previous theory.
Diagram showing blocks of Indian crust attaching to the base of the lithosphere after continental collision.
Credit: Sternai et al. 2025, Tectonics. Redistributed under Creative Commons CC BY 4.0 license.
This discovery opens new perspectives in geology. Adam Smith, an expert not involved, acknowledges the plausibility of the results. They could apply to other mountainous regions formed by continental collision.