The lithosphere on earth includes the rocky outer shell of the planet, the upper layer of mantle, and the crust. This layer, broken up into sections or tectonic plates, moves constantly and is responsible for the geological activity on earth. The lithosphere is about 60 miles deep in most places.
The lithosphere is preceded by the asthenosphere, the mantle, and outer and inner core strata of the earth. Because the lithosphere is always on the move, geologists believe that all of the landmasses on earth derived from a single continent, called "Pangea," as a result of thousands of years of steady movement, which formed the continents.