Is the theory of continental drift?

Answer 1

The idea that the continents were once one super-continent and subsequently moved apart is the basis of the theory of continental drift. Continental drift was first proposed as a scientific hypothesis with evidences by Alfred Wegener early in the twentieth century. Unfortunately, the evidence he was able to cite, such as similarities in coastline geographies and fossils on either side of the Atlantic, did not provide an explanation for the mechanism which caused it to happen. In Wegener's theory, the continents were somehow able to plow through the oceans. It wasn't until the mid-twentieth century that the Atlantic Ridge system was discovered. Further investigation revealed that the magnetic orientation of rock on either side of the ridge matched the orientation on the other side of the ridge, providing the proof for the mechanism that caused the continents to move apart. Basaltic magma was infilling the area on either side of the ridge to create new continental crust. Subduction of older, denser oceanic crust takes place at collision zones where it meets less dense oceanic and continental crust. The whole process is driven by gravity and heat from the Earth's interior via convection currents in the mantle. The process is no longer called continental drift, but is referred to as plate tectonics.
Alfred Wagner's theory was that the sea floor was spreading, causing the continents to 'drift'. The theory was originally tossed aside because the fact that the continents fitted together was not sufficient.