Alfred Wegener propounded the theory of plate tectonics in 1920.
The main features are-
1. The Earth's surface is made up of a series of large plates.
2. These plates are in constant motion travelling at a few centimetres per year.
3. The ocean floors are continually moving, spreading from the centre and sinking at the edges.
4. Convection Current beneath the plates move the plates in different directions.
5. The source of heat driving the convection currents is radioactive decay which is happening deep in the Earth.