(ORDO NEWS) — Throughout history, planet Earth has already had three supercontinent, and the fourth is on its way. Giant pieces of land converge and diverge again, each time in a different place. Geologists even managed to name this new supercontinent. When and what it will be – read the article.
New research provides some insight.
Colombia, Rodinia, Pangea – in the distant past, supercontinents appeared and disappeared on Earth. Scientists are now concluding that these gigantic parts of the land are formed in accordance with certain cycles, and this happens about once every 600 million years. They even predict when and where a new supercontinent could form, based on the creeping flow of rock in our planet’s hot mantle.
“It’s not a completely unexpected idea, but I like the way it is phrased,” says Paul Hoffman, a geologist and supercontinent expert at Harvard University who is not directly involved in this kind of research.
The continents sit on tectonic plates – crustal formations that float across the mantle. The mantle itself acts as a boiling pot of water – the Earth’s liquid crust heats the rocks at the bottom of the mantle, which causes them to slowly rise. At the same time, cooling pieces of crust in fault zones sink to the bottom of the mantle. This circulatory movement is called mantle convection, and over millions of years it causes the continental plates to move – as well as their occasional transformation into supercontinents.
To further explore this phenomenon, Ross Mitchell of the Chinese Academy of Sciences and his colleagues focused on mega continents, which are smaller than supercontinents. One such mega-continent is Gondwana, which was formed about 500 million years ago, and 200 million years later became the reason for the formation of Pangea.
To study how Gondwana became Pangea, specialists made a temporary map of the continental plates, based on fossil analysis and other temporal evidence. They also explored how the position of these continents relates to the movement of the mantle, as well as possible sites for ancient upwelling and downwelling.
They concluded that the continents are moving in the direction of the fault zones, where the mantle rocks cool and sink. Mitchell calls these zones “subduction girdles” because continental plates, which, because of their size, cannot sink, go there and there, he says, get stuck. They are only able to move horizontally and form continents, and this process can be compared to the transformation of Gondwana into Pangea. Representatives of the Mitchell team spoke about this in their report, which was published in November 2020 in the journal Geology.
Based on this model, we can assume what awaits our planet in the future. When Pangea collapsed 175 million years ago, it led to the formation of the Ring of Fire, a series of fault zones around the Pacific Ocean that feed volcanoes and earthquakes. Several continents have already come together to create Eurasia, the modern mega-continent that has already approached the Ring of Fire, the fault belt of our time. As Eurasia moves along the Ring of Fire, it will collide with the Americas at some point and a new supercontinent will form as a result. According to Mitchell, this will happen in 50 or 200 million years.
Geologists have named this new supercontinent Amasia. While opinions differ as to where the Amasia will end, Mitchell’s model suggests that it will be in the polar region, in the center of today’s Arctic Ocean.
“We can see a kind of rhythm in the evolution of the Earth,” says Damian Nance, a geologist at Ohio University and an expert on supercontinent motion. “It is not yet clear” if Mitchell was able to pinpoint this rhythm, but “the pendulum is shifting towards his pattern,” Nance added.
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