continental drift 
noun [mass noun]
The gradual movement of the continents across the earth’s surface through geological time.Despite the now compelling nature of much of the geological evidence for continental drift, the most unequivocal proof of the movement of continents now surely comes from palaeomagnetism....
- Geologists and continental drift theorists have shown that there was once one super continent named Pangea.
- When first proposed a generation ago, the theory of continental drift and plate tectonics was one of the most shocking scientific ideas of its day.
The reality of continental drift was confirmed in the 1960s, leading to the theory of plate tectonics. It is believed that a single supercontinent called Pangaea broke up to form Gondwana and Laurasia, which further split to form the present-day continents. Such movement continues today: South America and Africa, for example, are moving apart at a rate of a few centimetres per year.