Alfred Wegener’s Theory of Plate Tectonics

How do Continents move?

The German scientist Alfred Wegener came up with the theory of continental drift. It explains why:

• There are continents
• Continents move
• Earthquakes happen
• There are more earthquakes in some places than others
• Volcanoes form and erupt
• Mountains form
• New islands form

The start of the story is that there was once a large landmass named Pangaea. However, it broke apart into plates which are now our continents which we live on. These plates collide, move apart, rub against each other and submerge each other. While doing this they build up energy from friction. When this energy is released, that’s when earthquakes happen. The more energy stored, the more powerful the earthquake. Earthquakes happen on plate boundries.

For a volcano, one plate has to go under another, being submerged. As a plate gets submerged, the heat of the mantle melts the rock of the plate which it turns to magma. The magma because it’s hot, rises because it gets less dense. The magma rises through the plate on top and creates a tube in it’s path for more magma to come up through the volcano.

For a mountain range, either one plate goes on top of another and rises, or two plates collide and get forced up.

For an island to be formed anew, there needs to be two plates moving apart. As the plates move apart, magma comes out from the gap to create new, light oceanic rock. If there is enough magma to go above sea level and on, then that rock is now land. Hawaii was formed by magma like this.

Continents move because of convection currents. There are also two types of rock; continental and oceanic. Oceanic is denser so they get submerged when colliding with continental rock.