Scientists are reshaping our understanding of what supports the Himalayas, the tallest mountain range on Earth. For nearly a century, many believed that the weight of the Himalayas came primarily from a thick layer of crust. This idea stemmed from the work of Swiss geologist Émile Argand in 1924, who showed how the Indian and Asian crusts stack beneath the surface.
However, new research suggests there’s more to the story. Recent findings reveal a layer of Earth’s mantle sandwiched between these crusts, which explains why the Himalayas are so high and still growing. This discovery was led by Pietro Sternai, a geophysics professor at the University of Milano-Bicocca. He noted that the crust turns molten about 25 miles down, making it unsuitable to support the weight of large mountains: “Imagine building on yogurt!” he said.
The research team used computer simulations to analyze the collision between the Indian and Asian plates. Their models showed that as the Indian plate slid under the Eurasian plate and began to partially melt, blobs of the molten material rose to join with the base of the lithosphere, the rigid outer shell of the Earth.
This new model suggests a combination of crust and mantle beneath the Himalayas. The crust provides buoyancy, much like an iceberg floating in water, while the denser mantle adds strength and support. “The layered structure gives us just the right balance to keep the region uplifted,” Sternai explained.
To validate their theory, the researchers compared their simulation results with seismic data and rock samples. Their findings were consistent with geological observations that previous theories had struggled to explain. Simone Pilia, a co-author of the study, remarked that the new model clarifies many previously puzzling geological features in the region.
While the study brings exciting insights, it challenges the long-standing belief established by Argand. Adam Smith, a researcher at the University of Glasgow, noted that any shift away from this well-accepted theory is bound to stir debate within the scientific community.
Interestingly, introducing the concept of a mantle layer isn’t just speculation. Experts see it as a significant breakthrough. Douwe van Hinsbergen from Utrecht University praised the findings, considering them an elegant interpretation of how continental plates interact.
Overall, this research not only enhances our understanding of the Himalayas but also reflects a broader trend in science—where established theories may need revisiting in light of new evidence. As scientists continue to explore the mysteries of our planet, we can expect even more revelations about the forces shaping our world.
If you’re curious to learn more about Earth’s layers and other geological wonders, check out this quiz on planet Earth here.
