Researchers have predicted that a new megacontinent – Amasia – will form in the next 250 million years.
North and South America will crunch together, with the Caribbean Sea and Arctic Ocean disappearing, while Asia will join the Americas, according to new simulations from Yale University researchers and Japan’s Agency for Marine-Earth Science and Technology.
This will happen because of the movement of the earth’s tectonic plates – the enormous plates of the earth’s crust that have drifted together and apart over hundreds and millions of years.
The research, published in the journal Nature, is based on a theory called Orthoversion – after a supercontinent breaks up, the continents initially drift apart but become trapped within a north–south band of subduction – where one plate dips below another.
On our present-day Earth this band is the Pacific Ring of Fire, where the new supercontinent will form.
To test the model, researchers used paleomagnetic data – records of the Earth’s magnetic field preserved in rocks – to study variations in the rotation of the Earth with respect to its spin axis.
These variations, known as “true polar wander”, are caused by changes in the planet’s mass distribution; they are the Earth’s attempt to maintain rotational equilibrium – a re-adjustment that takes place over millions of years.
By combining these data with knowledge of how supercontinents affect the Earth’s motion, the researchers were able to predict Amasia.
The present-day Arctic Ocean and Caribbean Sea will vanish as North and South America fuse while they move northwards together, leading to a collision with Europe and Asia.
‘After those water bodies close, we’re on our way to the next supercontinent,’ said Dr Ross Mitchell, the paper’s lead author.
The research has also been supported by a paper published in the journal Geology by Dr Masaki Yoshida, a geologist based at Japan’s Agency for Marine–Earth Science and Technology (JAMSTEC).
The most recent supercontinent, Pangea (Greek for ‘All Lands’), formed about 300 million years ago with Africa at its centre.
It began breaking apart into the seven continents of today with the birth of the Atlantic Ocean about 100 million years later.
Researchers believe Pangea is the third or fourth supercontinent in Earth’s history.
Its immediate predecessors were Rodinia – which formed about 1 billion years ago – and Nuna, which formed about 1.8 billion years ago.
The idea of continental drift was introduced by German scientist Alfred Wegener in 1912, to explain how the shape of Earth’s countries looked suspiciously like jigsaw pieces that would fit together.
The Earth’s surface is formed from seven major and several minor tectonic plates that wander around at speeds varying from a few millimetres to two centimetres a year, the same pace that a human nail grows.
It’s the friction caused by plates grinding against each other that causes earthquakes.