Mattias Green, Hannah Sophia Davies and Joao C. Duarte writing for The Conversation
The outer layer of the Earth, the solid crust we walk on, is made up of broken pieces, much like the shell of a broken egg. These pieces, the tectonic plates, move around the planet at speeds of a few centimeters per year. Every so often they come together and combine into a supercontinent, which remains for some hundred million years before breaking up. The plates then disperse or scatter and move away from each other, until they eventually – after another 400-600 million years – come back together again.
The last supercontinent, Pangea, has been around 310 million years ago, and started breaking around 180 million years ago. It has been suggested that the next supercontinent will form in 200-250 million years, so we are currently about halfway through the scattered phase of the current supercontinent cycle. The question is: how will the next supercontinent form, and why?
There are four fundamental scenarios for the formation of the next supercontinent: Novopangea, Pangea Ultima, Aurica and Amasia. How each forms depends on different scenarios but are ultimately linked to how Pangea separated, and how the world's continents are still moving today.
The breakup of Pangea led to the formation of the Atlantic Ocean, which is still opening and getting wider today. Consequently, the Pacific Ocean is closing and getting narrower. The Pacific is home to a ring of subduction zones along its edges, where ocean floor is dropped down, or subducted, under continental plates and into the interior of the Earth. There, the old ocean floor is recycled and can go into volcanic plumes. The Atlantic, by contrast, has a large ocean ridge producing new ocean plate, but is only home to two subduction zones: the Lesser Antilles Arc in the Caribbean and the Scotia Arc between South America and the Antarctic.
If we assume that present day conditions persist, so that the Atlantic continues to open and the Pacific keeps closing, we have a scenario where the next supercontinent forms in the antipodes of Pangea. The Americas would collide with the northward drifting Antarctica, and then into the already collided Africa-Eurasia. The supercontinent that would then form has been named Novopangea, or Novopangaea.