Tectonic Plates Essay Sample
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Tectonic Plates Essay Sample
1.Wegener’s Theory-Continental Drift
Wegener’s developed the continental drift theory at the beginning of the 19th Century. He claimed that all the continents were joined together at one point in time, and drifted apart gradually over millions of years. Wegener stated that continents are not rigidly fixed, but moving at one yard per century.
Wegener published a book, The Origins of Continents and Oceans, which explained how billions of years ago the continents were once joined together in a large mass that he called “Pangaea”. Overtime this landform separated into small areas like “Gondwana”, “Laurasia” and finally to the positions we have now.
Why Was It Rejected?
Wegener’s theory was rejected because he had no direct proof to prove his theory. Also scientists of the time rejected this because at the time it was hard to believe as previous scientists had stated different facts, which clashed with Wegener’s theory, which proves that new information is hard to understand after you have been told a different thing for many years.
2.Evaluating Evidence for Continental Drift
The Plate Tectonics theory states that the outer layer of the earth, or lithosphere, is separated into different large slabs called plates, which are holding the continents and oceans. These plates are slowly moving and this helps us to understand that the continents were never in a fixed position, but also helps us to understand mountains, volcanoes, and other geologic events came to be.
Three pieces of evidence
* The coastlines of continents that are separated by ocean look as though they fit together (e.g. coastlines of Africa- coastlines of South America). I believe that this evidence is somewhat reliable because it is a very good observation that could lead to the theory that these continents once fit together and prove the tectonic plates, however just because they look like they might have fit together at one stage is not a lot of evidence supporting this as it might just be a simple coincidence. (E.g. a jig-saw piece may have the right shape to fit into another piece but the pictures may not match the picture correctly)
* The ocean floors are spreading away from oceanic ridges, which would imply that the continents are shifting cools and creates minerals to be magnetized, aligned with the Earth’s magnetic fields. The mid-oceanic ridges that are more than 650,000km long are the longest mountain ranges on the planet and moving of the continental plates would explain this movement. The mid-oceanic ridges are splitting because of hot magma that is rising out of these cracks and forming new crust this separates the old crust in a conveyer type movement. The form of new crust suggests that the whole crust is moving not just the continents. I believe that this evidence is very plausible and reliable as it shows that the plates are moving and the tectonic plates theory is proven. As the old crust separate because new crust is coming through proves that the crust is moving not just the continents.
* Fossils from the plant Glossopteris have been discovered on all 5 of the Gondwana continents. The seeds are too heavy to be carried by wind, and would have died quickly if placed in salt water, which indicates that the continents were once joined. Also fossils from several reptiles have been found on several separate continents, which would only make sense if they were joined together at some point. This evidence, I believe, is very reliable as this is the only conclusion that scientists have made so far for the existence of these fossils, as they cannot be carried by wind or in the ocean, the only reason why these fossils that are far apart is a result of the continents splitting up in the continental drift.
3.Explain the formation of mountains, volcanoes, locations of earthquakes, fold and faults by tectonic plates.
“Wegener and Continental Drift Theory.” The Church and Science:Conflict or Complement. N.p., n.d. Web. 21 July 2013. http://www.scientus.org/Wegener-Continental-Drift.html
“Continental Drift and Plate-Tectonics Theory | Infoplease.com.” Infoplease: Encyclopedia, Almanac, Atlas, Biographies, Dictionary, Thesaurus. Free online reference, research & homework help. | Infoplease.com. N.p., n.d. Web. 21 July 2013. http://www.infoplease.com/ipa/A0001765.html