Alfred Wegener's

Continental Drift Theory

Essay Topic:

Explain how Alfred Wegener turned his idea of continental drift into a “real” scientific theory. Be sure to mention the pieces of evidence he collected and how well they supported his idea.

Matching Coastlines

One of the main pieces of evidence which Wegener had found and which led to his theory of Continental Drift was the fact that South America and Africa fit together like a puzzle piece. The match between South America and Africa goes along the continental shelf all the the way to the tip of Africa. He felt that it wasn't just an accident of sea level that these two continents look alike and fit together. This is what led to Alfred Wegener to begin his theory of Continental Drift.

Shared Fossil Types

Two years after realizing about the matching coastlines of South America and Africa, Alfred Wegener also found fossils of the same species in two different continents which led to further proof for his theory. Fossils of the Mesosaurus were found in both South Africa and Brazil and the creature is too small for it to have swam across the Atlantic Ocean.

Mountain Ranges of the same age

Another main piece of evidence which supported the Continental Drift theory was that Wegener found mountain ranges that were similar and of the same age in two different continents. The mountain ranges in Brazil are very similar to the mountain ranges in Ghana. All of these mountain ranges appear to have the same age and to be formed of the same kinds of rock as well as beginning and ending at the same relative locations. This proof was not only found in between South America and Africa but also North America and Europe.

How the Continental Drift Theory Evolved

In Wegener's mind, he felt that he proved his theory. However, it was not supported by the community mainly because people didn't understand how the continents would have moved and drifted apart. The felt it was much too similar to the way the clouds moved and the theory was more like a meteorological forecast. In the 1960's, however, scientists found a stretch of underwater ridges on the ocean floor made up of continually erupting volcanoes. The Mid-Ocean ridge is formed when molten rock rises and pushes the crust apart. This created a vast spreading sea floor which is also strong enough to move the continents. With these new pieces of information, Wegener's theory is now believed to be true. Now we also know that our crust is divided into 12 major plates and they are all in constant motion.