Katherine Trigg 11RMi

Continental Drift

In these times the theory of Continental Drift is common knowledge to almost any educated person. The knowledge that the continents are slowly moving, is almost presumed knowledge to almost everyone, however this was most definitely not always the case. The theory of Continental Drift was first introduced 100 years ago by a scientist named Alfred Wegener. Wegener first became interested in the concept of continental drift when he came across a scientific paper that listed fossils of identical plants and animals that had been found on opposite sides of the Atlantic. Wegener became intrigued by this information and sought out to find greater pieces of evidence to support his theory, that at one point in time the continents were not separated by these large oceans that we know to be there today.

Wegener began to examine rocks from either side of the Atlantic. He noticed that in many cases the rocks that he examined in South Africa were similar if not exactly the same as those he examined in South America. Wegener also found that the fossils found in a certain place often indicated a climate utterly different from the climate of today: for example, fossils of tropical plants, such as ferns and cycads, are found today on the Arctic island of Spitsbergen. Wegener also began studying the coastlines of the continents. After studying numerous maps, he noticed that the Cape Town Mountains found in South Africa appear to be almost a continuation of the mountains located in Buenos Aires, Argentina on the other side of the Atlantic Ocean. Could these mountain ranges have once been joined together? This was the question that Wegener was set out to answer. Wegener believed that millions of years ago the coastlines of the continents fit together like a jig saw puzzle and he believed that they formed a super continent, which he called Pangaea.

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Wegener continued to expand his evidence when sonography was developed. Sonography uses echo signals to map the ocean floor. Sound signals would be sent down towards the ocean floor, and an echo sounder trace would calculate using the time it took for the sound signal to return to the boat, the depth of the ocean floor and that particular point. With this technology accurate maps of the ocean floor could be drawn. It was by using this technology that range of mountains was discovered running down the middle of the Atlantic Ocean. This range of mountains extended for approximately ...

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