The Theory of Plate Tectonics
The theory of plate tectonics concerns with the movement of the continental plates. It was paved from the theory of continental drift. The theory was proposed in 1915 by a German geologist and meteorologist named Alfred Wegener. He stated that parts of the earth's crust slowly drift atop a liquid core. He also stated how the earth ad a giant super continent called Pangaea.The theory includes much more than the movements of the continental plates. It also includes how the Himalayas are growing in height and how Iceland is slowly splitting into two. Plates move on the earth's crust due to convection currents in the upper mantle. Molten rock in the mantle expands due to heat and rises towards the surface. It then cools, spreads out and falls back towards the core due to gravity. This convection current is what makes the plates move. Plates move very slowly (only a few centimeters a year) and when two plates meet, there are three ways the plates can react. They can slide past each other, push against each other or move away from each other. Below is a map to show which direction the plates move when they meet.