Theory of Plate Tectonics and Related Evidence

Plate tectonics is the theory that the Earth's outer shell is divided into several plates that glide over the mantle as a result of convenction currents - circular movements of semi molten rock in the mantle.

Sea floor spreading (evidence)

In the centre of many oceans there are mid ocean ridges, underwater mountain systems with ridges of higher terrain on either side of a constructive plate margin. The mantle is under pressure from the crust above. As the plates move apart this pressure is…