EPT - Alfred Wegener and Continental Drift Lesson

 

Alfred Wegener and Continental Drift

While other scientists of the time had also noted the fossil anomalies across the continents, the prevailing theory was that they could be explained by "land bridges" that were now submerged. It took an inter-disciplinarian by the name of Alfred Wegener to come up with a new theory. Wegener was born in 1880 in Berlin, Germany. During his lifetime, he earned a degree in astronomy, and then turned his attention to studies in the fields of geophysics, meteorology, and climatology.

In 1911, he noted that, in addition to the widespread dispersion of fossils across multiple continents, that the continents themselves fit together like puzzle pieces. Also, when the continents are assembled in this fashion, mountain ranges in various continents connect to form much longer chains. For example, the Appalachian Mountains in North America, the Little Atlas of Morocco (in Africa) and the Scottish Highlands all line up when Pangaea is reconstructed. Geological examination of the minerals and rocks in these mountain ranges indicates that they are similar in age and materials, also suggesting that they were formerly connected.

These three lines of evidence - puzzle pieces that fit together, fossil ranges that lined up perfectly, and mountain ranges that link together - convinced Wegener that there was a better explanation than the current understanding of continents and the Earth's surface. He proposed that the continents were spreading apart from each other - drifting slowly through the Earth's crust - in a theory known as "continental drift".

If they are moving apart, Wegener argued, then logic suggests that they were closer together in the Earth's past. His theory proposed that all of the current land masses were joined together to form a supercontinent known as Pangaea approximately 300 million years ago, and that this land mass broke apart into the modern day continents.

Wegener faced years of almost unanimous ridicule for his theory. Geologists did not take kindly to an outsider challenging their long-held beliefs, and Wegener was unable to explain how the continents were able to move. He imagined that the continents pushed through the seafloor, like a ship pushes through water, and that it might be tidal forces or magnetism that produced the forces necessary to cause this motion. Neither of these explanations accounted for everything being observed, so Wegener's theory was roundly rejected. He died in 1930 during an expedition in Greenland - decades before another scientist found that piece of the puzzle.

 

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