Continental drift is the theory that our the earth's continents rest upon "plates" that float across the molten mantle of the earth. German scientist Alfred Wegner, was one of the first to state a hypothesis that such a thing can occur, but he did not have sufficient evidence to support his claims. Until the late 1950's, this idea was barely known of, but in the 60's evidence was linked to it, bringing it to the public's eye once more. Continental drift is closely related to the idea of plate tectonics, and one is rarely mentioned without the other. Plate tectonics states that the Earth is divided into many plates that move at large scales, this being the basis for continental drift, encompassed the latter theorem and thusly; the two became merged. Seafloor spreading is also a part of these ideologies, and is often used in support of the theory of continental drift. There are many different, proven motions or evidences that can support the theories stated above, all of them circumstantial, but there are so many of such in number that the above stated theories can be sufficiently proved without the use of definitive evidence.
Seafloor Spreading.
Seafloor spreading can help to support the theory of continental drift by stating that not only do the plates move, but the seafloor apparently moves with them. When plates are subducted at boundaries, the rock is melted into magma. This magma travelsi through the mantle until it reaches a mid-ocean ridge, where volcanic activity pushes it up into the sea, where it is instantly cooled and once more turned into rock. This rock accounts for "new" crust in oceanic plates, and as the new crust grows in, the older crust towards the edge of the oceanic plate is pushed down and further out into a subduction zone near a continental boundary.
Magnetic Anomalies.
Magnetic anomalies in seabed rocks further supports continental drift and plate tectonics by supporting seafloor spreading and rock upwelling at mid-ocean ridges.
