You know that there are seven continents on Earth today. But did you know that in the past, the Earth looked very different? Sometimes there were more continents. Sometimes there were fewer continents.
How did the continents form? The answer is plate tectonics. Plate tectonics is the idea that the rocky surface of the Earth is made up of enormous pieces of rock, or plates. These plates float on top of a flowing, molten layer of rock. The rocky plates are moved along by the flow of the molten rock underneath them. As they move molten rock gets pushed up to the surface in some areas. In other areas, plates crash together. Sometimes the edge of one plate gets pushed underneath the edge of another.
During the Proterozoic Eon there were hundreds of small pieces of crust floating on the mantle. These first land masses were small continents and island arcs. They collided with each other because of plate tectonics. The pieces of crust jammed together. Much energy was released. The pieces fused together.