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How the Earth can be seen in 200 million years



The outer layer of the Earth, the solid crust that we live in, consists of broken fragments, like broken eggshells.

These pieces, tectonic plates, move around the planet at speeds of several centimeters per year.

Every now and then they gather and join as supercontinents, remaining for several hundred million years before breaking up, Conversation reported.

The plates then spread or spread and moved away from each other, until finally – after another 400-600 million years – came back together again.

The last supercontinent, Pangea, formed around 310 million years ago, and began to break down around 180 million years ago.

It has been suggested that the next supercontinent will be formed in 200-250 million years, so we are currently halfway through a separate phase of the current supercontinent cycle. The question is: what is the shape of the next supercontinent, and why?

There are four fundamental scenarios for the formation of the next supercontinent: Novopangea, Pangea Ultima, Aurica and Amasia. How each form depends on different scenarios but ultimately relates to how Pangea separated, and how the continents of the world are still moving today.

The outbreak of Pangea caused the formation of the Atlantic Ocean, which is still open and increasingly widespread. As a result, the Pacific Ocean closes and gets narrower.

The Pacific is home to a subduction zone ring along its edge ("fire circle"), where the ocean floor is torn down, or subcontracted, under the continental plate and into the interior of the Earth.

There, the old ocean floor is recycled and can become volcanic rock.

The Atlantic, on the other hand, has a vast ocean ridge that produces new oceanic plates, but is only home to two subduction zones: the Bow of the Small Antilla in the Caribbean and the Scotia Arc between South America and Antarctica.

1. NOVOPANGEA

If we assume that the current conditions persist, so that the Atlantic continues to open and the Pacific continues to close, we have a scenario where the next supercontinent is formed in Pangea antipodes.

America will collide with Antarctica which was carried north, and then to Africa-Eurasia which has collided.

Supercontinents which will then be formed are named Novopangea, or Novopangaea.

2. PANGEA ULTIMA

The Atlantic opening may, however, slow down and really start to close in the future.

Two small subduction arcs in the Atlantic have the potential to spread along the east coast of America, which leads to Pangea reforms as America, Europe and Africa are brought back together into a supercontinent called Pangea Ultima.

The new continent of the supercontinent will be surrounded by the super Pacific Ocean.

3. AURICA

However, if the Atlantic would develop a new subduction zone – something that might have happened – both the Pacific and the Atlantic Ocean could be destined to be closed.

This means that a new ocean basin must be formed to replace it.

In this scenario Pan-Asian rifts currently cut Asia from western India to the open Arctic to form new oceans. The result is the formation of the Aurica supercontinent.

Because Australia's northern currents to the north will be the center of a new continent because East Asia and America cover the Pacific from both sides.

The European and African plates will then rejoin America when the Atlantic closes.

4. AMASIA

The fourth scenario predicts a fate that is totally different for the Earth in the future. Some tectonic plates are currently moving north, including Africa and Australia.

This motion is believed to be driven by anomalies left by Pangea, deep in the interior of the Earth, in a section called the mantle.

Because of this northern current, one can imagine a scenario in which continents, except Antarctica, continue to fly north.

This means that they will eventually gather at the North Pole in the supercontinent named Amasia. In this scenario, most of the Atlantic and Pacific will remain open.

From these four scenarios we believe that Novopangea is the most likely. This is a logical development of the current direction of the continental plate shift, while the other three assume that other processes come into play.

A new Atlantic subduction zone is needed for Aurica, reversal of the opening of the Atlantic for Pangea Ultima, or an anomaly in the interior of the Earth left by Pangea for Amasia.

Investigating the tectonic future of the Earth forces us to push the boundaries of our knowledge, and think about the processes that make up our planet on a long time scale.

It also directs us to think about the Earth's system as a whole, and raises a series of other questions – what is the climate of the next supercontinent? How will ocean circulation adjust? How will life evolve and adapt?

These are the types of questions that push the boundaries of science even further because they push the boundaries of our imagination.

This article originally appeared on The Conversation and was republished with permission.

By Mattias Green, Reader in Physical Oceanography, Bangor University; Hannah Sophia Davies, PhD Researcher, Universidade de Lisboa; Joao C. Duarte, Researcher and Coordinator of Marine Geology and Geophysics Group, Universidade de Lisboa.


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