Recent research has uncovered a fascinating mechanism behind the formation of high plateaus in the interior of continents, attributing their rise to deep, slow-moving processes within the Earth. The study, led by Thomas Gernon, a geoscientist at the University of Southampton, suggests that as continents break apart, they set off a chain reaction deep within the Earth’s mantle. These disturbances generate Earth mantle waves that propagate inward from the edges of the continents over tens of millions of years, eventually leading to the uplift of vast inland plateaus.
The study, published in the journal Nature, focuses on three iconic coastal escarpments formed during the breakup of Gondwana, Earth’s last supercontinent. These escarpments include the Western Ghats in India, the Highland plateau in Brazil, and the Great Escarpment in South Africa. The researchers demonstrated that these escarpments, which align with ancient continental boundaries, were created by the same rifting process that triggered Earth mantle waves. These waves slowly moved towards the continent’s core, lifting the strong, stable continental interiors, known as cratons, to form the high plateaus we see today.
The research team used a combination of topographic maps and computer simulations to trace the origins of these geological features. They found that the Earth mantle waves were responsible for the inward migration of uplift and erosion on the plateaus, occurring at the same time and speed as the mantle waves churned below. This finding was significant because it suggested that the formation of both the escarpments and the inland plateaus was driven by a single, continuous process set off by continental breakup.
The process, although slow, is remarkably powerful. The study found that the Earth mantle waves move at a pace of just 9 to 12 miles (15 to 20 kilometers) every million years. However, over the course of millions of years, these waves dramatically reshaped the landscape by peeling away the strong roots that anchor the continents at the crust-mantle boundary. As these roots were removed, the cratons became more buoyant and began to rise. Over time, wind and rain further eroded these areas, making them even lighter and more buoyant, which culminated in the formation of the stable, high plateaus observed today.
The researchers suggest that this process could explain other similar geological formations, such as the cliffs and plateaus in North and South Carolina or those south of Cameroon. The study posits that these features might be remnants of earlier continental breakups, with erosion over millions of years having erased the more dramatic evidence of mantle churn and uplift.
Additionally, the study connects the formation of these landforms to other geologic processes, including the eruption of diamonds from deep within the Earth. The same Earth mantle waves that uplift plateaus are also thought to have facilitated the upward movement of diamonds, linking these seemingly disparate geological phenomena.
This research not only provides a new understanding of how some of Earth’s most dramatic landscapes are formed but also highlights the profound and far-reaching effects of Earth mantle waves on the planet’s geological history.