A new study suggests that dramatic cliffs and high plateaus were caused by the same wave that was triggered in the Earth’s middle layer when the continents broke apart. New research suggests that high plateaus in the interior of continents were raised by drilling deep into the Earth, hundreds of kilometres from where they formed.
As continents break apart, massive walls of rock can rise at the boundaries where the crust breaks apart. A new study finds that this breakup causes a surge in Earth’s middle layer, the mantle, that has been slowly rolling inward for tens of millions of years, triggering the uplift of the plateau.
Lead author Thomas Gernon, a scientist at the University of Southampton in the United Kingdom, said scientists have long known that continental rifts cause massive escarpments to grow, such as the rock walls that separate the East African Rift Valley from the Ethiopian Plateau. And these craggy rocks sometimes lie at the edge of interior plateaus that rise from strong, stable cores of continents known as cratons.
But because the two landscape features typically formed tens of millions to 100 million years apart, many scientists believe the different formations resulted from different processes, Gernon told Live Science in an email.
In a new study published Aug. 7 in the journal Nature, Gernon and his colleagues examined three iconic coastal cliffs that formed during the breakup of Earth’s last supercontinent, Gondwana. One runs along the coast of India, around the Western Ghats for about 1,200 miles (2,000 kilometers); another in Brazil encircles the Highland Plateau for about 1,900 miles (3,000 km); and the Great Cliffs of Southern Africa encircle the Central Plateau, covering an astonishing 3,700 miles (6,000 km), according to the study. Inland plateaus in these regions can rise a kilometer or more, Gernon said.
The team used topographic maps to show the slopes aligned with continental boundaries and suggested they were created by a rift. Computer simulations showed that continental rifts disrupt the mantle, causing deep waves to roll inward toward the center of the continent.
Source: Port Altele
