Live Science has a story about the what is holding up Himalayas and it’s it isn’t what we thought. Scientists had theorized the crumpled region caused by the squeezing of Tibet by the tectonic forces of the Indian sub-continent colliding with the Asia had doubled the thickness of Earth’s crust beneath the Himalayas and Tibetan Plateau to the north. That extra thickness alone carries the weight of the mountain ranges. That theory was published by Swiss geologist Émile Argand in 1924. It shows the Indian and Asian crusts stacked on top of each other, together stretching 45 to 50 miles (70 to 80 km) deep beneath Earth’s surface. Evidence had called the theory into question. Now, research published in the journal Tectonics found there is a piece of mantle sandwiched between the Asian and Indian crusts, which may explain why the Himalayas grew so tall.

The mantle is the layer of Earth that sits directly beneath the crust. It is much denser than the crust and, therefore, doesn’t liquefy at the same temperatures. Meanwhile, the crust is so light and buoyant that it behaves similarly to an iceberg, lifting up higher above Earth’s surface the thicker it gets.

Sternai and his colleagues discovered the mantle insert by simulating the collision between the Asian and Indian continents on a computer. The model showed that as the Indian plate slipped beneath the Eurasian plate and started to liquify, blobs of it rose and attached themselves not to the bottom of the Asian crust, but to the base of the lithosphere, which is the rigid outer layer of the planet composed of the crust and upper mantle.

This is fundamental, Sternai said, because it means there is a rigid layer of mantle between the stacked crusts solidifying the whole structure beneath the Himalayas. The two crusts give enough buoyancy to keep the region lifted, while the mantle material provides resistance and mechanical strength. “You’ve got all the ingredients you need to uplift topography and sustain the weight of the Himalayas and Tibetan plateau,” he said.