The Early Earth and Plate Tectonics.

Tectonic plates is a scientific theory that describes the large scale.

The theory is that it builds up on older concepts of Continental Drift.

Alfred Wegener created the Continental Drift theory. It's the biggest theory of all time. (Refer to "Continental Drift" page.)

Seafloor Spreading was developed in the 1950s. Seafloor Spreading- a process that occurs at mid-ocean ridges where

new oceanic crust is formed through volcanic activity and then slowly moves away from the ridge.

The lithosphere is broken up into different tectonic plates.