Definitions: Pangea theory - The Pangaea theory states that all present continents were once together and collectively known as a 'supercontinent' called a Pangaea. The word 'Pangaea' means 'all lands' in Greek, defining the way the continents were 200 millions years ago before it split up.  Tectonic plates - The two sub-layers of the earth's crust that move, float, and sometimes fracture and whose interaction causes continental drift, earthquakes, volcanoes, mountains, and oceanic trenches.  Subduction - A geologic process in which one edge of one crustal plate is forced below the edge of another.  Animation   Further reading: Wiki