Plate Tectonics - Why and How the Plates Move

The main features of plate tectonics are: The Earth's surface is covered by a series of crustal plates. The ocean floors are continually moving, spreading from the center, sinking at the edges, and being regenerated. Convection currents beneath the plates move the crustal plates in different directions.
The heat that drives convection is created from radioactivity that is the product of chemical reactions taking place within the Earth's mantle and core.
All the observations described above, along with many other studies of our planet, support the theory that underneath the Earth's crust (the lithosphere: a solid array of plates) is a malleable layer of heated rock known as the asthenosphere which is heated by radioactive decay of elements such as Uranium, Thorium, and Potassium.


Brooklyn College - Geology Department