INTRODUCTION

The continental drift hypothesis was developed in the early on part of the 20th century, mainly by Alfred Wegener. Wegener sassist that continents move around on Earth’s surface and also that they were as soon as joined together as a solitary supercontinent. While Wegener was alive, researchers did not believe that the continents might move.

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THE CONTINENTAL DRIFT IDEA

Find a map of the continents and also cut each one out. Better yet, use a map where the edges of the continents present the continental shelf. That’s the true size and also shape of a continent. Can you fit the pieces together? The easiest attach is between the eastern Americas and also western Africa and also Europe, however the rest have the right to fit together also (figure 1).

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api/deki/files/1204/CD_Figure_2.png?revision=1&size=bestfit&width=486&height=158" />Figure 2. The similarities between the Appalachian and also the eastern Greenland also mountain arrays are evidences for the continental drift hypothesis.

Ancient fossils of the very same species of extinct plants and pets are uncovered in rocks of the exact same age but are on continents that are now extensively separated (figure 3). Wegener proposed that the organisms had lived side by side, but that the lands had actually relocated acomponent after they were dead and fossilized. He said that the organisms would not have actually been able to take a trip across the oceans. Fossils of the seed fern Glossopteris were too heavy to be lugged so much by wind. Mesosaurus was a swimming reptile yet can only swim in fresh water. Cynognathus and also Lystrosaurus were land reptiles and were unable to swim

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Figure 3. Wegener used fossil proof to assistance his continental drift hypothesis. The fossils of these organisms are found on lands that are now far apart.

Grooves and rock deposits left by prehistoric glaciers are uncovered this day on different continents incredibly cshed to the equator. This would certainly indicate that the glaciers either formed in the middle of the sea and/or spanned many of the Earth. Today glaciers just develop on land also and also nearer the poles. Wegener thought that the glaciers were focused over the southern land also mass close to the South Pole and also the continents moved to their existing positions later. Coral reefs and also coal-creating swamps are discovered in tropical and also subtropical atmospheres, however prehistoric coal seams and also cdental reefs are uncovered in places where it is a lot also cold now. Wegener argued that these creatures were alive in warm climate areas and that the fossils and also coal later had actually drifted to brand-new places on the continents.

Take a look at this computer animation mirroring that Earth’s climate belts remajor in roughly the very same place while the continents relocate and this animation showing exactly how the continents break-up up.

Although Wegener’s proof was sound, many nlinux.orglogists at the time rejected his hypothesis of continental drift. Why perform you think they did not accept continental drift?

Scientists argued that tbelow was no method to define just how solid continents might plow with solid oceanic crust. Wegener’s principle was almost forgained till technological developments presented even even more evidence that the continents moved and also offered researchers the tools to build a device for Wegener’s drifting continents.


MAGNETIC POLARITY EVIDENCE

Puzzling brand-new evidence came in the 1950s from researches on the Earth’s magnetic history (figure 4). Scientists provided magnetometers, gadgets qualified of measuring the magnetic field intensity, to look at the magnetic properties of rocks in many kind of areas.

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api/deki/files/1207/CD_Figure_5.png?revision=1&size=bestfit&width=429&height=305" />Figure 5. Earth’s current north magnetic pole is in north Canada.

Older rocks that are the very same age and also are situated on the same continent allude to the same area, however that location is not the present north magnetic pole. Older rock that are of various eras execute not allude to the very same places or to the current magnetic north pole.

In various other words, although the magnetite crystals were pointing to the magnetic north pole, the place of the pole appeared to wander. Scientists were amazed to uncover that the north magnetic pole adjusted area via time (figure 6).

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To test this, nlinux.orglogists fitted the continents together as Wegener had done. It worked! Tright here has actually just been one magnetic north pole and the continents have actually drifted (number 7). They called the phenomenon of the magnetic pole that seemed to relocate but actually did not noticeable polar wander.