EVIDENCES OF CONTINENTAL DRIFT THEORY.pptx

Evidences that supports the Continental Drift Theory

1. CONTINENTAL DRIFT THEORY

2. In the early days, geologic phenomena such as earthquakes and volcanic were thought to be caused by supernatural forces. It was though that the planet was formed the way it is. These ideas started to change radically in 1915 when Alfred Wegner, a German meteorologist, introduced the Continental drift theory in his book, The Origin of Continents and Oceans . He proposed that a long time ago in the geologic past, the continents formed a single land mass, which he called Pangea, that broke into several continents and drifted to their current position

3. The Fit of Continental coast lines Although it was previously pointed out by observers before him, Wegner viewed the apparent fit of the continents along their coastlines as pieces of a jigsaw puzzle-an indication that the continents were once joined together. For example, the coast of Africa fits well with the eastern coast of South America and the southeast coast of North America

4. Distribution of Glacial Sediments Wegner plotted in the map the location of the sediments and rocks that were formed during the last glaciation of the late Paleozoic. He also analyzed the orientation of the striations or the scratches imprinted as glaciers moved along the surface of rocks. These sediments are present in southern parts of South America, Africa, India, Australia, and Antarctica.

5. Paleoclimate If the southern part of Pangea is located in the polar region as indicated by the presence of glaciers, then it follows the rest of the supercontinent extended to the equatorial region and to the Northern Hemisphere. As observed today, the equatorial region has a tropical climate characterized by conditions the favor lush vegetation such as abundant rainfall and warm temperature.

6. Distribution of fossils Paleontologist have distinguished fossils or remnants of organisms preserved in rock that are indicative of marine and terrestrial organisms. Some terrestrial organisms are restricted in certain continents because they cannot swim or cross over the vast oceans that presently separate the continents. Wegner mapped the distribution of fossils of known land organisms and he found out that there are fossils of the same organism in certain places in several continents. This can only be explained by the existence of a single landmass that would have allowed the organisms to migrate across dryland.

7. Distribution of fossils Cynognathus Lystrosaurus Mesosaurus Glossopteris

8. Distribution of Rocks Wegner was able to recognize the distinct assembly of rocks occurring on either side of the Atlantic Ocean. Based on the type, age, and sequence of layering, these appear to be immediately adjacent to each other if the Atlantic Ocean is closed and Pangea is reconstructed

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