Continental drift – what is it?

Continental drift is the theory that continents can drift apart from one another

The History and development of the continental drift theory In 1915 Alfred Wegner developed the theory of “Continental Drift”. Alfred didn’t come up with this theory all by himself. He combined evidence from several different scientists.

Sir Francis Bacon In 1620 Sir Francis Bacon noticed by looking at a map that there was a “very good fit” between some of the continents

Antonio Snider Pellegrini In 1858 French Scientist Antonio Pellegrini cited that fossils of the same plant and animal species were found on both sides of the Atlantic Ocean.

Other research Other research indicated that glacial grooves don’t match as the continents are positioned today but they would match if the continents had been put together in their proposed original arrangement

Alfred Wegner’s theory of Continental drift was not accepted! Even though Alfred Wegner had combined evidence from many different sources to show that the continents had once been connected and then drifted apart his theory was not accepted because he did not explain “HOW” the continents moved.

Later … Frank Taylor In 1958 An American Geologist named Frank Taylor pointed out geologic similarities between South America and Africa. Similar Rocks found on both sides of the Atlantic Evidence of the same climate Frank Taylor could not explain how the plates moved either and so his observations were also “dismissed”

Harry Hess gets the job done! In the 1960’s Harry Hess, an American Geologist and an armed service veteran from World War II, discovered that the sea floor splits apart in the center of the Atlantic ocean at areas called mid ocean ridges. He used sonar to map the ocean floor, and to identify German U boats!

Mapping the ocean floor!

Sea Floor Spreading explains “continental drift”

Continental drift explains Pangea and the moving continents

All of this leads to the “Theory of Plate Tectonics”

Picture citations http://universe-review.ca/I09-03-drift.jpg http://www.sciencedaily.com/images/2007/06/070615152639.jpg http://www.scientificamerican.com/media/inline/blog/Image/Laser-seabed.jp http://media.maps.com/magellan/Images/NGC_Jun_1968b_c.jpg