Differences and Similarities Between Plate Tectonics and Continental Drift
First, since there are many similarities between Plate Tectonics and Continental Drift, let's brush up on the definitions of the two. Plate Tectonics is a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the asthenosphere. Continental Drift, however, is a theory developed by Alfred Wager who suggested that in the past, there was a super continent called Pangaea. Over time, this super continent split apart to form the seven continents we have today. One of the key difference between the newer plate tectonics and continental drift theories is that Wegener's original theory of continental drift, and the more modern ideas called plate tectonics is that Wegener believed that each continent was propelled through the solid ocean floor. Some geologists thought this was completely absurd. The newer theory of plate tectonics states that the entire crust of the earth is broken into six large plates and many, many smaller ones. Any plate may consist of ocean floor and/or part of a continent or islands. The boundaries between plates are the mid-ocean ridges, where new oceanic crust is formed and plates move apart; ocean trenches and young mountains, where plates come together and older ocean crust is overridden and returned to the interior. A similarity between the two theories, however, is that both of the theories suggest the Earth is constantly moving. The theory of plate tectonics suggests that the plates that float on top of the asthenosphere, which hold continents, are always moving, and therefore have a tendency to bump into each other. Places where the plates meet each other are known as faults. There are usually some very large earthquakes near, or in faults. A very large fault, called the San Andreas fault, is located in California. The theory of Continental drift, suggests a very similar idea. However, this theory states that all the continents once fit together into a very large continent. There is plenty of evidence that supports this, too. You can find very similar fossils, and geology on both the east coasts of South America, and the west coast of Africa. Plus, they look like they could fit together, too. There is also similar evidence on both the east and west coasts of the U.S. and Europe. Although there are more similarities than differences, you have to remember that both theories suggest the exact same thing.