Continental Drift/ Plate Tectonics
Gracie Hudson
Continental Drift
Continental drift was a theory that explained how continents shift position on Earth's surface. The theory was made by Alfred Wegener, he explained why all of the look-alike fossils are found on different continents.There was once a supercontinent called Pangaea
Fossil Evidence
The two types of evidence are that Wegener found rocks and fossils that are on different continents that match up with each other. The fossils are found on one continent then are also found on another continents which tells us that the continents were once together.
Rock Evidence
The rocks that were found on more than one continent were found to match up like puzzle pieces. Also if you look at Africa's and South America's shorelines they look like they can fit together.
Plate Tectonics
The theory that the outer shell of the Earth is made of plates. There is a hard, rocky layer that protects the mantle. This outer layer is called the lithosphere.
Sea Floor Spreading
Sea floor spreading, magma rises and cools to make new crust at oceanic ridges.This is divergent boundaries. This shows that there are plates that move under the sea floor.
Earthquakes and Volcano Mapping
When people map earthquakes and volcanoes they notice that they constantly land in the same places over and over. The earthquakes and volcanoes are happing in the same places because of the plate boundaries. People think that because the earthquakes and volcanoes happen in the middle of the continents that, that is where the center of the plates are.
Hot Spot
A hot spot is a area under the crust that is hotter than usual causing the magma to rise. The hot spots are not found close to plate boundaries. It is found that they stay in one place. People think the hot spot stays in one place while the plates move around it.