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The Continents Were Once Joined Together
Abraham Ortelius theory was that the continents were once joined together. His evidence was that the coastlines of Africa and South America looked like they fit together. People did not agree with this theory because the scientific community at this time thought that this idea was fake so they did not accept it. -
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Plate Tectonics Theories
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Continental Drift Theory
Alfred Wegner came up with this theory. He said that the continents had once formed a super continent called Pangaea. The evidence that he used was the similar coast lines between countries and that there were the same types of organisms and rocks on countries that are now separated by oceans. The scientific community did not agree with this theory because Alfred Wegner could not explain what caused the continents to actually move. -
Convection From The Mantle
Arthur Holmes proposed the theory that convection from the mantle is what was causing the continents to drift apart. He used radioactivity and the results he got from that to support his theory and provide evidence. The scientific community disagreed with this theory because he would need much more evidence and data to prove his theory than he would of had access to at the time. -
Sea Floor Spreading
Henry Hess came up with the theory that the sea floor is spreading. The mid ocean ridge and flat topped mountains called guyots under the sea were his evidence. This theory was not accepted by the scientific community however it did provide an answer to the question that Wegners theory left. How do the continents move. -
Earths Magnetic Field
Frederick J. Vine and Drummond Holy worked together to create the theory of that the earths magnetic field reverses over time due to metals that come up from the mantle through the mid ocean ridge. The evidence that they had was patterns on the sea floor near this ridge. The scientific community did not agree with this theory because there was not enough evidence to support this theory like how long this takes to happen. -
Patterns on the Sea Floor
Lawrence Morley proposed the thief that rocks on the ocean floor showed the direction of earths magnetic field. His evidence came from the patterns on the sea floor and that they now believed that magma was coming up from the mid ocean ridge and cooling causing sea floor spreading. Most people did not agree with him because this idea was so crazy and hadn't been really researched until then. -
Math and Plate Tectonics
Dan McKenzie theorized that there are about two layers in the mantle. He used math and physics to find his evidence and see that the mantle was divided into two main sections. This theory has been accepted by the scientific community because it helps prove how and why the continents on earth move. -
Earths Zones
W. Jason Morgan theorized that the crust consistes of many different sections that are separated by boundaries. The evidence that he found was from when he was in the navy and he noticed large lines on the ocean floor. He also used lots of math and geometry. This theory has been accepted by the scientific community because we now have the technology to actually prove this.
