February 1, 2023

The world’s landmass will unite to form a new supercontinent. Meet Amasia

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Geologically, the Earth is very active — it was active in the past, it’s active now, and it will continue to be active for many years to come. According to the new study, the constant movement of tectonic plates will push the continents together, forming a new supercontinent with a big desert at its heart.

A possible Amasia configuration 280 million years into the future. Credits: Huang et al (2022).

If you were to go back in time a long enough period and take a look at the planet from space, you’d likely be confused by what you see.

The Earth’s surface hasn’t always looked the same. Our planet’s crust is split into rigid plates called tectonic plates. These aren’t fixed in place: they move at a speed of a few centimeters per year (a speed similar to how fast your nails are growing). From year to year, there’s no major difference, nor from century to century or even millennium to millennium — but go back 10 million years, and you’ll see the difference.

Some plates move towards one another, some move away from each other, and sometimes, plates just brush against one another. In the Earth’s geologic history, this has been a continuous process, and it’s continuing now. The Atlantic is currently growing at a rate of a few cm per year, and the Pacific is shrinking at a similar speed. So the configuration of the continents and the oceans will change as the Pacific disappears and the Atlantic grows into a mega ocean.

Some geologists also expect the continents to come together and form a supercontinent, something which has also happened in the past, most famously with the continent of Pangea. During the time of Pangea, there was one big ocean around the continents, Panthalassa. A similar scenario is likely to happen again, says Chuan Huang, from Curtin University.

The continent of Pangea on which today’s political map has been overlaid.

“Over the past two billion years, Earth’s continents have collided together to form a supercontinent every 600 million years, known as the supercontinent cycle. This means that the current continents are due to come together again in a couple of hundred of million years’ time,” Huang said.

So Huang and his colleagues set out to analyze and predict future plate movement.

“Currently, Earth consists of seven continents with widely different ecosystems and human cultures, so it would be fascinating to think what the world might look like in 200 to 300 million years’ time,” says co-author Zheng-Xiang Li, also from Curtin’s School of Earth and Planetary Sciences.

According to their findings, our new supercontinent of Amasia is about to form — eventually. In about 280 million years, most of the landmass on the planet will fuse together.

“By simulating how the Earth’s tectonic plates are expected to evolve using a supercomputer, we were able to show that in less than 300 million years’ time it is likely to be the Pacific Ocean that will close, allowing for the formation of Amasia, debunking some previous scientific theories.”

Supercontinents form by the closure of either internal or external oceans, but now, the Earth is at a point in history when only the external oceans can close. This is because of the distribution of oceanic crust, which is thinner but denser than continental crust.

The formation of this supercontinent will change many things on the planet. The interior, for instance, will be cut off from humid winds and will become a hot desert.

“Earth as we know it will be drastically different when Amasia forms. The sea level is expected to be lower, and the vast interior of the supercontinent will be very arid with high daily temperature ranges,” Professor Li said.

But the good news is that most of Amasia’s landmass will be clustered around the same latitude it is today. Some previous models suggested that landmass will accumulate around the North Pole, which would have made the planet less hospitable, but the new model suggests that Earth will be habitable and hospitable for a pretty long time.