Future supercontinent, Amasia, named for its fusing the Americas and Asia by closing the Arctic Ocean and Caribbean Sea.
Credit: Mitchell et al, Nature
Predicted convergence directions (red arrows) are confined within the 'ring of fire' of subduction zones (blue band). Amasia will be located 90˚ away from the geographic centre of the last supercontinent, Pangea, near present-day Africa.
Credit: Mitchell et al, Nature
CAMBRIDGE: A new supercontinent will form around the Arctic in approximately 100 million years, according to a new model that uses the geological history of the Earth's surface to predict its future.
The study, published today in Nature, challenges the traditional ideas of how the Earth's land comes together and drifts apart over time. Not only does it allow us to predict how and where the next supercontinent - dubbed 'Amasia' - will form, but helps to understand how the world came to be as it is today.
"We found a way to measure the angular distance between successive supercontinents," said lead author Ross Mitchell from Yale University in the U.S. "Our result has relevance both to our concepts of the internal workings of the Earth and to better understanding of its changing surface."
The supercontinent cycle
Supercontinents form in cycles, with all the land on Earth coming together every few hundred million years. The last of these supercontinents was Pangaea, which was centred on modern day Africa and broke up approximately 200 million years ago, as the other continents drifted away.
Traditional models predict that successive supercontinents form either in the same place, through a process known as 'introversion', or on the opposite sides of the globe, through the process of 'extroversion'. The new research shows that geological evidence fits neither of these models.
Analysing the alignment of magnetic elements in ancient rocks reveals where the magnetic poles and continents were during specific periods of the Earth's history. The Yale researchers brought together such measurements from multiple studies to calculate the positions of Pangaea and the two preceding supercontinents, Rodinia and Nuna.
Fusing the Americas and Asia
The calculations showed that both Rodinia and Pangaea formed at approximately 90 degrees to their respective supercontinental predecessors. With results that fitted neither the introversion nor extroversion models, Mitchell and his colleagues have proposed a new one.
"We present a third alternative, which we call 'orthoversion', between those two completely opposing models," said Mitchell. "But ours is not merely a fuzzy middle-ground solution; it specifies a transitional style that is precisely in the middle."
With its basis in historical supercontinent formation, the new model also provides credible predictions about the future of our planet's surface.
"Now that we have a dominant theory for how supercontinents take form, we can speculate how the continuation of the supercontinent cycle into the future will play out," said Mitchell, "Our new model ... would predict that the Arctic Ocean and Caribbean Sea will close, fusing the Americas and Asia practically at the North Pole."
Nothing more fundamental
Brendan Murphy from the Department of Earth Sciences at St Francis Xavier University in Canada thinks the study will be of value to the geological community. "It's certainly an elegant model," he said, "and any model that provides a unified and plausible explanation for a number of enigmatic events drives us forward. I think what it'll do is stimulate the geomagnetic community and tectonic community to go out and test this model. Even if [it] is wrong, over the years we'll learn a lot by testing it."
Murphy also highlighted the importance in understanding these processes, which have shaped our cosmological home.
"The evolution of the planet [has] provided all the Earth's endowment of resources, created the chemical and physical environment for life, and its cycles are correlated with long-term climate change," he said. "There's arguably nothing more fundamental for us as humans than to understand our natural environment and the evolution of it. The supercontinent cycle has been probably the main driver of that over the past two and half billion years."
Center of Origin of Continents:
The equator, the primordial superdense-sole-landmass (the Stem-Continent:Pangaea), is the center of common origin (not Africa), of all today's different Continents of the Earth, Africa included. Aiya-Oba (Philosopher).