Plate Tectonics

Koester

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Continental Drift Summary

I think that Continental Drift is valid. I think this because of the evidence we have and what I have learned. Some of the evidence that I have is the same freshwater fossils were found on South America and Africa, Which would've been way too long for the reptile to swim from continent to continent. This reptile was living on the continents when they were connected. Another clue is that the SAME plant fossils were found on Africa, Australia, India, South America, and Antarctica. This plant fossil was from when the continents were joined together. Fossils of warm weather plants were found on the island of Spitsbergen in the Arctic Ocean. These plants could have never gotten here unless the continents were joined together at one time. There was glacial deposits found in Tropical regions! Similar rock structures were found all over different regions. This would've never been possible unless the continents were connected at one time. This is why I believe that Continental Drift is valid.

Some Continental Drift pictures

Seafloor Spreading

Summary

The seafloor spreads apart when the hot, less dense material which is magma below earths crust flows sideways which carries the seafloor away from the ridge in both directions. The young and old rocks go into the continental crust and melts down into magma at the subduction zone. Once the magma cools down it makes new seafloor. The magma becomes denser and sinks helping form the ridges. The north and south poles switch directions as the seafloor spreads out. This process starts over and makes new seafloor as it goes. I do believe this theory is valid from the information I learned.

Plate Tectonics