Shortly before the dawn of the era of the dinosaurs - about 251 million years ago - the continents of the Earth adjoined each other, merging into the supercontinent Pangea. This land mass, which straddled the equator like the ancient Pac-Man, eventually split into Gondwana in the south and Laurasia in the north.
The fate of the earth
Gondwana and Laurasia were further divided into seven continents that are familiar to us today. But the constant movement of the tectonic plates of the Earth raises the question: "Will there ever be another supercontinent like Pangea?"
The answer is yes. Pangea was not the first supercontinent to form in Earth's 4.5 billionth geologic history, and it certainly won't be the last.
What is plate tectonics? Tectanic plates?
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“This is one part of the debate that isn't much of a controversy,” Ross Mitchell, a geologist at Curtin University in Perth, Australia, told Live Science. "But what 'the next Pangea' will look like is where opinions really differ."
Geologists agree that there is an established, fairly regular cycle of supercontinent formation. This has happened three times in the past. The first was Nuna (also called Columbia), which existed between 1.8 and 1.3 billion years ago. Then came Rodinia, which dominated the planet between 1.2 and 750 million years ago. Thus, there is no reason to think that another supercontinent will not form in the future.
The convergence and spread of continents is associated with the movement of tectonic plates. The earth's crust is divided into nine main plates that slide across the mantle, the fluid layer that sits between the core and the semi-solid crust. In a process called convection, hotter material rises from the Earth's core to the surface, while colder mantle rocks sink. Rises and drops of material either spread the plates apart, or force them together by pushing one below the other.
How do GPS navigators help?
Scientists can track plate tectonic movements using GPS instruments. But in order to piece together what these plates were millions of years ago, paleogeologists have to turn to natural magnets in the earth's crust. When hot lava cools at the junction where two plates collide, some rocks in the lava that contain magnetic minerals like magnetite coincide with the Earth's magnetic fields. As the cooled rock moves through plate tectonics, scientists can use this alignment to calculate where, in terms of latitude, these magnets have been located in the past.
A new supercontinent forms every 600 million years or so, Mitchell said, but this cycle could be accelerating. This suggests that the next Pangea, dubbed Amasia (or Pangea Proxima), will form earlier than we expect. Mitchell believes that the cycle is accelerating because the internal heat of the Earth, accumulated in the planet's core since its formation, is dissipated, which means that convection is faster.
“Given that Pangea flourished probably 300 million years ago, we should wait for Amasia here in 300 million years,” Mitchell said. "But perhaps it will form in 200 million years."
However, predicting the year of birth of Amasia is not easy.
What will happen next?
“The difficulty in predicting the Pangea of the future is that you can't take the modern plate movement as a constant unit and move quickly forward,” adds Mitchell. Plate movements can change unexpectedly, and imperfections in the seabed cause the plates to deviate from their trajectories.
Currently, according to Matthias Green, an oceanographer at Bangor University in the United Kingdom, California and East Asia are converging towards Hawaii, while North America is moving farther and farther from Europe. Meanwhile, Australia is drifting north on the collision course with Korea and Japan, while Africa is turning north towards Europe. These movements, of course, occur at the rate of centimeters per year, at the rate at which hair and nails grow in humans.
Mitchell and Green said there are several prevailing ideas about what the next round of the Tetris geology game might look like. The Atlantic Ocean could close, with Northern Canada crashing into the Iberian Peninsula, and South America colliding with South Africa roughly where Pangea used to be.
Or the Pacific Ocean could disappear, swallowed up by Asia and North America. Mitchell had another, non-standard hypothesis - North America and Asia could move northward to converge over the Arctic, suppressing the Arctic Ocean.
So how could the formation of the next Pangea affect life on Earth (assuming there is still flora and fauna in 300 million years)?
The answer is - life on Earth will totally change. After all, the last global extinction of species occurred precisely during the split of Pangea.
Madina Kemova