Meet Amasia: Earth's next supercontinent will form in the next 200-300 million years

Researchers at the New Curtin University in Australia used a supercomputer to determine what the world would look like when the next supercontinent is formed. According to their calculations, a new supercontinent of Amasia, a combination of present-day American and Asian continents, will be formed in 200 to 300 million years, a press release said.

Underneath the still exteriors, our planet is undergoing a massive churn that manifests itself over millions of years. Last week, Interesting Engineering reported how scientists study rare finds from deep below the Earth's surface to gain insights into the working of the inner Earth.

Now, researchers at the Earth Dynamics Research Group and the School of Earth and Planetary Sciences at New Curtin University have used a supercomputer to forecast what could be the likely effect of the movement of the giant tectonic plates.

The formation of continents

Over the past two billion years, the Earth's continents have collided to form a supercontinent on multiple occasions. Called the supercontinent cycle, this occurs every 600 million years and brings all the continents of the world together.

Over 700 million years ago, the previous supercontinent started breaking apart and began shrinking the Panthalassa super ocean. The ocean that was the largest at its peak when the dinosaurs roamed on Earth continues to shrink by a few centimeters even today and is commonly known as the Pacific Ocean.

Yet the ongoing supercontinent cycle means that over the course of the next 200-300 million years, the Pacific Ocean will shrink from its current expanse of thousands of miles and bring the continents of America and Asia together to form Amasia.

According to the calculations made by the researchers, the younger oceans, such as the Atlantic and the Indian Ocean, are unlikely to close in the next round of tectonic plate movements. Interestingly, the continent of Australia will also have a role to play, as it is expected to collide with Asia first before Amasia formation occurs.

What will Amasia be like?

Currently, the geographical locations of the seven continents have major bearings on the environment and ecosystems on these landmasses. Even human cultures are influenced by the prevalent conditions. So, researchers are keen to know what life on the supercontinent will be like.

According to the researchers, the planet can be expected to be drastically different when the supercontinent is formed. Water levels in the seas are expected to be lower, with the interiors of the supercontinent turning into arid regions. The daily temperatures are also expected to have high ranges.

The research findings were published in the journal National Science Review last week.

Abstract

Earth's known supercontinents are believed to have formed in vastly different ways, with two end members being introversion and extroversion. The former involves the closure of the internal oceans formed during the breakup of the previous supercontinent, whereas the latter involves the closure of the previous external superocean. However, it is unclear what caused such a diverging behavior of supercontinent cycles that involved first-order interaction between subducting tectonic plates and the mantle. Here we address this question through 4-D geodynamic modeling using realistic tectonic setups. Our results show that the yield strength of the oceanic lithosphere plays a critical role in determining the assembly path of a supercontinent. We found that high oceanic lithospheric strength leads to introversion assembly, whereas lower strength leads to extroversion assembly. A theoretically estimated reduction in oceanic crustal thickness, and thus its strength, during Earth's secular cooling, indicates that introversion was only possible for the Precambrian time when the oceanic lithosphere was stronger, thus predicting the assembling of the next supercontinent Amasia through the closure of the Pacific Ocean instead of the Indian-Atlantic oceans. Our work provides a new understanding of the secular evolution of plate tectonics and geodynamics as the Earth cooled.