Oct 08, 2022 I Paul Seaburn

Earth is On Its Way to Having Just One Supercontinent Again

Would you like to drive from London west and end up in Paris without ever having to put your car on a ferry or cross over a bridge? How about walking from Los Angeles to Tokyo without ever getting your feet wet? Those trips could happen someday … although you won’t live long enough to make the trips in your Tesla or Nikes. A new study shows that the Pacific Ocean is shrinking and the continents are shifting – a combination that will someday merge North and South America, Europe, Asia, Africa, Australia and Antarctica into one supercontinent called … Allica? Amessica? Whatever it is called, it would be a good idea to own property at the North Pole because that is where scientists predict the center will be. Does Santa know something we don’t?

“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.”

Dr Chuan Huang, from the Curtin University Earth Dynamics Research Group and the School of Earth and Planetary Sciences, gives the gory details in a Curtin University press release announcing the publication of his new study in the National Science Review. While a few people outside the planetary science community know that today’s seven continents (or fewer, if you adhere to the merged Eurasia or Afro-Eurasia continents nomenclatures) were once part of a supercontinent called Pangaea, which was a long, nearly pole to pole land mass centered at the equator. Pangaea formed about 335 million years ago, and began breaking apart about 200 million years ago, around the beginning of the Jurassic era. However, a few scientists like Dr. Huang believe there were as many as ten supercontinents prior to Pangaea going back 3.6 billion years in Earth’s4.5 billion year history. That was part of the data he and his research team fed into a supercontinent simulator on a supercomputer to determine if and when we will be on our way to another mashed merger of mass.

“Earth's known supercontinents are believed to have formed in vastly different ways, with two endmembers being introversion and extroversion. The former involves the closure of the internal oceans formed during the break-up 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.”

In simple terms, if Earth has one supercontinent, then it must also have one super-ocean. To form that super-ocean, one or more of today’s oceans will have to disappear, drain or dry up. While one would expect the largest ocean – the Pacific – to be the winner, that wasn’t what the simulator showed … and this was just the first of many surprises.

“The resulting new supercontinent has already been named Amasia because some believe that the Pacific Ocean will close (as opposed to the Atlantic and Indian oceans) when America collides with Asia. Australia is also expected to play a role in this important Earth event, first colliding with Asia and then connecting America and Asia once the Pacific Ocean closes.”

The key element of this supercontinent simulation is the shifting of Earth’s tectonic plates. The researchers were shocked to find that the models showed the Amasia supercontinent forming less than 300 million years from now … and the reason is that the Pacific Ocean has been shrinking much faster than expected. Don’t worry … this is one phenomena not being exacerbated by climate change. The Pacific is the planet’s oldest ocean, having formed 700 million years ago from the Panthalassa super ocean that was separated into the smaller oceans during the breakup of the Pangaea supercontinent. At a shrinkage rate of a few centimeters per year, its current 10 thousand kilometers will be gone in possibly as few as two hundred million years from now.

Yes, that is much too far into the future to plan an ‘Around the World in 80 Day in a Car Without a Bridge’ excursion, it is still worth modeling as climate change continues to affect the levels of Earth’s oceans and land masses, as co-author Zheng-Xiang Li  from Curtin’s School of Earth and Planetary Sciences explains:

“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. 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.”

The press release gives a proposed drawing of what the Amasia blob will look like with shadows of the former continents inside it – Australia ends up landlocked approximately in the middle. This is not what Pangaea looked like, nor any of the prior supercontinents. Before it was Gondwana and before that was Pannotia, which was almost entirely in the Southern Hemisphere. Before that, Rodinia had what is now Australia and Antarctica in the Northern Hemisphere, forming from Columbia, which was mostly in the Northern Hemisphere. These mergers and breakups go all the way back to Vaalbara, which emerged from the then planet-covering ocean 2.7 to 3.6 billion years ago after four large meteorite impacts between 3.2 and 3.5 billion years ago, and is the source of the earliest of Earth’s fossils and rocks.

“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.”

While we should still be concerned with climate change and global warming, the simulations shows that the disappearance of the Pacific and the formation of Amasia can only occur during a time of global cooling. The ecosystem will most certainly look different than it does today. Will it include the descendants of modern humans? That depends … can you imagine all humans living in one country called Amasia? Can you imagine them getting along?

Paul Seaburn

Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

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