The Shifting of Pangea

The Shifting of Pangea

Have you ever noticed that a map of the world looks like a puzzle and the continents look like the pieces that would fit together to complete the puzzle.

In 1912, Alfred Wegener, a German scientist and an adventurer, came up with a theory that the continents had once been part of a "supercontinent". Wegener proposed that, over 200 million years, what he called Pangea had separated and became individual pieces. Pangea means "all lands" in Greek, and that is what Pangea was, a very large landmass when all of the continents were connected. When Wegener first proposed this idea in 1912, people did not buy into this theory. One of the problems that Wegener faced was that he believed that the continents had drifted apart, but he couldn't explain how they had drifted apart. Another problem was that there was a theory already in place called the "Contraction Theory". This theory stated that the Earth was once a molten ball and in the process of cooling, the surface cracked and folded up on itself. One of the problems with this theory was that it suggests that all mountain ranges were the same age, and this could not be true. Wegner's explanation was that continents shifted and these shifting plates would collide, encounter resistance from one another, compress, then fold upwards to form mountains near the edges of the plates.

Eons ago India and an ancient ocean called the Tethys Ocean sat on a tectonic plate. This place was shifting northward towards Asia at a rate of 10 centimeters per year. The ocean got progressively smaller unit about 55 million years ago when it collided with Asia. There was no more ocean left of lubricate the subduction and so the plates formed the High Plateau of Tibet and the Himalayan Mountains.

Evidence that Pangea may have existed can be found in land animals, vegetation, mountains, and the climate. Fossils and plants that are the same, can be found on different continents, across oceans. Assuming that the land was once connected, animals could have walked across the large land mass and not have to swim. For example, the mesosauras (a land animal) could not have traveled from South America to Africa because of the Atlantic Ocean. Yet, there are fossils of this animal on both continents. Another example is there are trees in South America, Africa, India, Australia, and Antarctica that are of the same origin. How would the seeds have traveled over so many different continents? One explanation is that the lands were once connected.

Other evidence is the formation of mountains. The Appalachian Mountains are found in North America as well as the British Isle and Scandinavia, which is now separated by the Atlantic Ocean. The mountains are of the same age and structure.

More evidence why scientists believe in the Pangea hypothesis is the climate. Since the Southern Hemisphere was once by Antarctica and the Northern Hemisphere was once by