|geology See also plate tectonics the theory that the earth's continents move gradually over the surface of the planet on a substratum of magma. The present-day configuration of the continents is thought to be the result of the fragmentation of a single landmass, Pangaea, that existed 200 million years ago|
|continental drift |
A theory stating that the Earth's continents have been joined together and have moved away from each other at different times in the Earth's history. The theory was first proposed by Alfred Wegener in 1912. While his general idea of continental movement eventually became widely accepted, his explanation for the mechanism of the movement has been supplanted by the theory of plant tectonics. See more at plate tectonics.