A Continental Drift
By Shanuka Kadupitiyage
You might remember that we talked about a supercontinent that existed long before Pangaea ever did. You might have been surprised to hear that because Pangaea is usually what we hear about the most when it comes to supercontinents. Today, if you keep reading, you’ll learn all about this really cool term ‘continental drift’ and the many supercontinents that existed long ago; yes, there were a lot of them.
Continental drift After years of studying, a German scientist named Alfred Wegener had a theory that the continents we see on the map today were once upon a time, part of one massive supercontinent, before they broke and drifted apart. You could prove this by taking all the continents and trying to put them together like a big jigsaw puzzle. What Wegener couldn’t explain was how this happened. He thought it was because of the Earth spinning. Later, this theory was replaced with the theory of plate tectonics. Although this is a little complicated, in the simplest of terms, it means that the surface of the Earth is made up a bunch of plates, which move because of the pressure of the magma underneath. In fact, these tectonic (Tek-Tonik) plates are moving right now, and are the reason why earthquakes happen, and how mountains were created. Is there proof? Of course, you might wonder how Wegener managed to prove this to everyone.
First there is the fact the continents can all fit together like a puzzle piece. Also, Wegener pointed out that the rock formations and fossils found in Brazil looked a lot like the ones found in West Africa, where they would have been connected to each other. This is a very old theory and took a lot of time to prove. Not everyone believed him, but Wegener believed in what he knew was right. It took years, but people started to believe him once more proof was discovered. Supercontinents A supercontinent is when all of the Earth’s continents group together to create a single, giant continent.
The last supercontinent to have been on Earth was Pangaea, which was in the time of the dinosaurs. You have to remember that supercontinents can be both big and small. The ocean was very different during different time periods, especially during each Ice age (yes, there were many). The oldest supercontinent we know of was Vaalbara, which was there during the time when life on Earth had just begun, and the oldest types of bacteria and other microbes (yes, germs were the first Earthlings) started to appear. Then we have other supercontinents along the time such as Ur, Kenorland, Arctica, Atlantica, Columbia (Nuna), Rodinia, Pannotia and Gondwana, which was before Pangaea. Some of them aren’t technically supercontinents, but they did exist in some point of time. Will it happen again? That’s a good question. Although most of the Earth’s continents are separate, they are still moving, just really slowly. A few centimetres each year. Pangaea broke apart around 180 million years ago, and it’s very likely that millions of years later, it can happen again. Of course, the world would be a very different place by that time.