Plates Project

Michelle Henningsen

Summary

Continental Drift is possible because of animal fossils, plant fossils, climate, and similar rock layers. Animal fossils of the reptile Mesosaurus have been found in South America and Africa. This reptile cannot swim in salt water, so how could it go swim between the continents? Plant fossils of the Glossopteris have been found in Africa, Australia, India, South America, and Antarctica. This plant could not possibly grow in all these different climate areas. Fossils of warm weather plants were found on an island in the Arctic Ocean. Wegener hypothesized that this island drifted from the tropical regions to the arctic. Similar rock structures have been found on different continents. Parts of the Appalachian Mountains of the western United States are similar to those in Greenland and western Europe. For these reasons, continental drift makes sense, but I don't believe this theory.

Summary

Seafloor spreading is where magma under the oceanic crust is pulled upwards into the mid-ocean ridge. The old rocks in the mid-ocean ridge are pushed towards the continents and the new magma in the mid-ocean ridge becomes the newer younger rocks. The old rocks are then pushed under the continental crust and then down into the subduction zone. In the subduction zone, the old rocks under the continents are melted into magma again and the process starts over. This theory I believe to be true because the magma rising and sinking when heated or cooled causes continental drift because it is pushing the continents apart and causing continental drift and plate tectonics to move by pushing them away

Summary

Plate tectonics can happen in three forms. Convergent, divergent, and transform. Convergent can happen in continent vs. continent, oceanic vs. oceanic and oceanic vs. continental plates. This plate boundary causes trenches, volcanoes, mountains, magma, collisions, crumpling and folding. Divergent can happen between oceanic vs. oceanic and continental vs. continental plates. This kind of plate boundary causes seafloor spreading, ridges, new rock, magnetic pull reversals, mountains, volcanoes, and rift valleys. Transform boundary can happen between all plates and cause rock catching, tension, pressure, rocks breaking, and earthquakes. Seafloor spreading and continental drift both cause plate tectonics to move.