The New Supercontinent of Amasia
Amasia is the working name given to the continent that likely will be produced when Eurasia and North America bump into each other. Scientists are a bit vague about when this will happen, suggesting it could take place anywhere between 50 million and 200 million years from now. So, there’s plenty of time to make survival plans.
The Mechanics of Plate Tectonics
The tectonic plates of the Earth, on which continents sit, are always moving on a drifting layer called the asthenosphere; this is made up of rock that is squishy enough to flow. But, it doesn’t flow in a way we would recognize, such as water does; it flows on a geologic timescale measured by a few metres a century.
Some plates move faster than others. The Indo-Australian plate is the Formula 1 of geology, moving at about 15 cm a year. About 70 million years ago it collided with the southern part of the Eurasian Plate. The impact of one continent slamming into another, even in slow motion, was enough to throw up the Himalayan Mountain range. The collision is still ongoing and the mountains are still rising.
Creation of Supercontinents
One of the people involved in a new Yale University study predicting the creation of the enlarged continent is Ross Nelson Mitchell. He is quoted by The New York Times as saying: “The fusion of North and South America together will close the Caribbean Sea and meet Eurasia at the present-day North Pole.”
The Yale study suggests that Australia is moving north and will drift into Asia somewhere between Japan and India. Africa will then close up behind Australia and this will mark the creation of another supercontinent.
As the BBC reports, “The continents are last thought to have come together 300 million years ago into a supercontinent called Pangaea [sometimes Pangea].” Geologists have hypothesized that other super-continents have formed; Rodinia about one billion years ago, and Nuna about 800 million years before that.
Previously, researchers had thought the new supercontinent would form in the mid-Atlantic region as Pangaea had or on the other side of the world in the current Pacific Ocean. The new study suggests the North Pole as a more likely meeting point.
What Was Pangaea Like?
Let's wind the geological clock back 300 million years or to see what Pangaea might have looked like. We get the word Pangaea from the Ancient Greek word “Pan”, meaning entire, or complete, and “Gaia,” another Greek word meaning Earth.
This continent straddled the equator although most of it was in the southern hemisphere. It was surrounded by a single ocean named Panthalassa. Again, we’ve gone to the Ancient Greek for “Pan” and “Thalassa” meaning sea.
The supercontinent covered about one third of the Earth’s surface. Its centre must have been arid as it was far from any sources of rainfall. However, the equatorial region must have been covered by lush vegetation. This is known because coal deposits in Europe and America were laid down when plants died and were compacted into the mineral.
Small mammals lived on Pangaea as did insects such as cicadas and beetles. Many reptile species thrived, among them, the ancestors to today’s crocodiles and birds. However, the landscape was dominated by dinosaurs.
About 200 million years ago, Pangaea began to break apart, driven by the same dynamic forces that brought the supercontinent’s constituent parts together in the first place.
Study of Magnetic Forces
According to Kerri Smith, writing in Nature, the Yale scientists analyzed “the magnetism of ancient rocks to work out their locations on the globe over time, and measured how the material under Earth’s crust, the mantle, moves the continents that float on its surface.” From this data they foresee the new supercontinent forming over the Arctic.
Smith writes that Ross Mitchell and his colleagues “think that this is part of a pattern: Pangaea formed at about 90 degrees to the previous super-continent, Rodinia, and Rodinia at about 90 degrees to Nuna …” This model is called orthoversion and seems to clear up a puzzle surrounding continental drift. It was thought to be random but now it appears to follow a sequence.
Other Tectonic Possibilities
There seems to be general agreement among scientists that the drift of tectonic plates can be predicted with reasonable confidence about 85 million years into the future.
But, geologist Ronald Blakey cautions “When it comes to extrapolating future geologies, things become very complicated very quickly.” He says the historical record shows several completely unexpected shifts. These will likely happen again throwing off carefully calculated scenarios.
Meanwhile, geologist Christopher Scotese thinks what he calls Pangaea Proxima is a more likely story line; it would be similar to the Pangaea of 200 million years ago he says.
However, Scotese is also cautious about such forecasts. He told NASA “It’s all pretty much fantasy to start with. But it’s a fun exercise to think about what might happen. And you can only do it if you have a really clear idea of why things happen in the first place.”
- According to Live Science, “Many scientists figure Earth began as one huge continent—dry as a bone. Water was delivered in comets, the thinking goes, and then the oceans developed.”
- The North American and Eurasian tectonic plates, for example, are separated by the Mid-Atlantic Ridge. The two continents are moving away from each other at the rate of about 2.5 centimetres (one inch) per year. So, when Christopher Columbus first sighted what is now the Bahamas, the islands were 44 feet closer to Europe than they are today.
- In 1953, Tenzing Norgay and Edmund Hillary became the first people to reach the summit of Mount Everest. As the peak is growing at the rate of 2.4 inches a year (six centimetres), it is now 22.3 feet (6.8 metres) higher than in 1953. If we go back 26,000 years, Everest was a full mile shorter than today.
- “America and Eurasia ‘to Meet at North Pole.’ ” Neil Bowdler, BBC News, February 8, 2012.
- “Next Super-continent Will Form in Arctic, Geologists Say.” Sindya N. Bhanoo, New York Times, February 8, 2012.
- “Supercontinent Amasia to Take North Pole Position.” Kerri Smith, Nature, February 8, 2012.
- “History of the Supercontinent Pangaea.” Amanda Briney, ThoughtCo, December 11, 2019.
- “Continental Drift.” National Geographic, undated.
- “Have There Always Been Continents?” Live Science, November 10, 2012.
- “What Did the Continents Look Like Millions of Years Ago?” Geoff Manaugh and Nicola Twilley, The Atlantic, September 23, 2013.
- “Continents in Collision: Pangea Ultima.” NASA Science, October 5, 2000.
© 2020 Rupert Taylor