It’s been estimated that in all of Earth’s history, there have been 7 supercontinents, with the most recent one being Pangaea.
The next supercontinent (Pangaea Ultima) is expected to form in around 250 million years.
Why is this the case? What phenomenon causes these giant landmasses to coalesce, break apart, then coalesce again?
In: 1126
The chunks of crust that makes continents is kind of like ice cubes floating on water, but made out of the lightest kinds of rocks, and they’re floating on hot magma.
The chunks of crust under the oceans are similar, but made of heavier kinds of rock.
When continents bump into oceans, the continental crust usually goes on top of the ocean crust and it sinks back into the mantle.
When two continents bump into each other, both are too light to go down into the mantle, so they crunch up and make big mountains and get stuck together.
This happens over and over until all of the continents make one big continent.
And because the mantle is basically “boiling” all the time, hot spots (like bubbles of steam, but made of melted rock called magma) form randomly under the crust. The heat has to go somewhere, so it cracks the crust open and forces the big continent to break back apart.
This happens over and over over hundreds of millions of years.
Latest Answers