The consequences of continents splitting are likely felt in far-off lands, too. A new study has linked continental break-up to new topological features forming in stable lands, according to a new study.
The study published in Nature provides answers to why new topological features like plateaus and ‘escarpments’ (kilometre-high steep slopes) form. The Earth’s internal structure is made up of the outermost crust, the mantle and the core (inner and outer core).
When tectonic plates move away, the lithosphere, which comprises the upper mantle and crust, thins. This results in the splitting up of a continent.
During this process, steep coastal escarpments emerge at the rift margins, which are major geological objects that mark the transition between continents and oceans. Subsequently, the interior plateaus rise vertically further inland, Tom Gernon, associate professor at the University of Southampton, and lead author of the study, told Down To Earth (DTE).
The researchers also explain why the stable parts of continents called ‘cratons’ like the Sahyadri hill range in the Western Ghats, eastern Brazil, and southern Africa, which are far from such escarpments, rise vertically.
By using advanced computer models and statistical methods, the team investigated how the Earth’s surface has responded to the breakup of continental plates through time.
In response to the continental breakup and the stretching of the Earth’s crust, the mantle experiences some stirring motions, the study pointed out.
It sets off a ‘deep mantle wave’, which travels along the continent’s base at about 15-20 kilometres per million years.
This wave, according to the study, removes layers of rock that form the base of continents. “Much like how a hot-air balloon sheds weight to rise higher, this loss of continental material causes the continents to rise — a process called isostasy,” said Professor Brune.
Jean Braun, Professor at the University of Potsdam, explained that a sequence of events linked to continental split-up likely helps the escarpment and the stable, flat plateau, form.
The same mechanism can also explain why diamonds quickly rise from 150 km of below the Earth’s surface onto the surface.
As for the impact on climate, the researchers explain that extreme levels of erosion that leads to plateau formation can also draw down carbon dioxide from the atmosphere.
Gernon explains that the formation of great escarpments and elevated continental plateaus produces a physical barrier that can drive the formation of new species. “Here, populations of organisms diverge into genetically distinct species due to adaptation to different ecological niches or environments,” he adds.
Further, the uplift of land by hundreds of metres to over a kilometre could do two things. It could either push some plants out of their comfort zone or force them to adapt to different climatic environments, the expert highlighted. The researchers hope to determine if this process occurs globally in other continental regions.