Giant waves in Earth’s mantle can cause continental uplift

New research suggests that giant waves in the Earth’s mantle, caused by continental breakup, could be responsible for the formation of dramatic landforms such as high plateaus and steep cliffs. When continents break apart, huge cliffs often rise at the boundaries where the Earth’s crust separates. This breakup generates waves in the mantle that propagate inward for tens of millions of years, causing plateaus to uplift.

Published on August 7 in Nature, this study sheds light on a geological process that connects these features via deep mantle waves. Thomas Gernon, a geoscientist at the University of Southampton and lead author of the study, emphasizes that these formations were previously thought to be the result of different processes. However, this new research suggests that they have a common origin.

Gernon and his team focused on three prominent escarpments that formed during the breakup of Gondwana, Earth’s last supercontinent. These included the escarpment along India’s Western Ghats, a escarpment surrounding Brazil’s highland plateau, and the Great Escarpment in South Africa. Their analysis showed that these escarpments are similar to continental rifts, indicating that they formed through the same process. Computer simulations confirmed that rifting disturbances in the mantle create deep waves that move inward and influence the rise of plateaus.

The study also examined mineral data, which showed that the uplift and erosion of these plateaus occurred synchronously with mantle waves. These waves travel very slowly, about 9 to 12 miles per million years, and peel away the strong roots that anchor the continents. This gradual process causes the continents to become more buoyant, leading to their uplift.

The research suggests that similar mantle wave processes could explain other escarpment and plateau regions worldwide. However, older formations may have been significantly altered by erosion, making them more difficult to study. This work underscores how ancient geological processes can have a lasting impact on Earth’s landscape.