continental drift theory

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  1. 1. The Continental Drift, is a theory that proposed that all of the continents were once a single land mass known as PANGAEA. This theory was proposed by ALFRED LOTHAR WEGENER
  2. 2. ALFRED WEGENER - A German Scientist, in the year of 1912 who proposed Continental Drift Theory.
  3. 3. Evidence Although, Wegener didn't have any proof, there was evidence discovered supporting the theory by several scientists. Unfortunately, the evidence was gathered after Wegner passed away. There are approximately five pieces of evidence that support the theory of the Continental Drift.
  4. 4. PANGAEA EVIDENCE 1. Jig saw puzzle of continents
  5. 5. PANGAEA EVIDENCE 2. The similar ancient animals and plant fossils, found on the edges of various continents. fossil of a Glossopteris Fossil of a Mesosaur fossil of a Cynognathus Fossil of a Lystrosaurus
  6. 6. PANGAEA EVIDENCE This is a map of Pangaea, showing the continents connected and showing the matching fossils of plants and animals.
  7. 7. PANGAEA EVIDENCE 3. Identical rock sequences and age. - Basically meaning, various countries have identical rock sequences. For Example, South America and Africa have identical rock sequences, because they were joined when Pangaea existed.
  8. 8. PANGAEA EVIDENCE 4. North America and Europe having the same mountain ranges. - there have been mountain ranges found in North America and Europe that are identical, proving the theory.
  9. 9. PANGAEA EVIDENCE 5. The climatic conditions. - There have been glacial deposits founded in the tropics and coal founded in Antarctica. This supports the theory of the Continental Drift, because coal originates from tropical plants, which can only be founded in the tropics. Additionally glacial deposits can only come from Antarctica, proving the theory.
  10. 10. PANGAEA EVIDENCE This photo shows the glacial deposits founded in various continents
  11. 11. Although, this is the theory believed by many scientists today, many were skeptical about Wegener's theory during his period of time. Many were skeptical, because he couldn't prove the theory of the Continental Drift, although he proposed the idea. Furthermore, he couldn't prove the movement of the continents. However, after Wegner passed away, it was proven that the movement of the continents, resulted from the motion of crustal plates.
  12. 12. Seafloor Spreading provided insight to the mechanism for how the continents moved. The magma which pushes up at the mid-ocean ridge provides the new land pushing the plates, and the subduction zones gobble up the land on the other side of the plates. The mechanism was convection currents!
  13. 13. Thirteen plate on the world
  14. 14. Pangaea about 200 million years ago, before it began breaking up. The southern portion of Pangaea GONDWANA, and the northern portion LAURASIA.
  15. 15. As the seafloor spreads apart at a mid-ocean ridge, new seafloor is created.
  16. 16. Plate tectonic explain Earthquakes Mountains volcanoes
  17. 17. Earthquakes and volcanoes occur mostly along or nearEarthquakes and volcanoes occur mostly along or near trenches and mid-ocean ridges...trenches and mid-ocean ridges...
  18. 18. Continents look like they could be part of a giant jigsaw puzzle
  19. 19. Distribution of fossils of several organisms supported The theory that the continents were once joined together
  20. 20. Francis Bacon (1561-1626) first noted how coasts of Africa and South America fit.
  21. 21. Mesosaurus, a fresh water reptile that couldnt swim across the open sea
  22. 22. Same rock patterns found in South America, India, Africa, Antarctica and Australia
  23. 23. Mountains in South America and Antarctica are believed to have formed as part of the same mountain chain.
  24. 24. Tropical plant remains (coal deposits) found in Antarctica Glaciations in Africa, South America, India, and Australia during the same time
  25. 25. Deposits found in Antarctica. Coal requires a warm, lush climate ===> Whats Antarctica like today? ===>
  26. 26. Fossils of Glossopteris are found in Permian rocks of South Africa, India, Australia, South America, and Antarcticaall regions that were once part of Gondwanaland.
  27. 27. No mechanism for movement of continents Wind and currents could possibly move fossils Theory was not accepted by scientists

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