Chapter 13 Plate Tectonics Review Questions
Alfred Wegner developed the theory of continental drift which states that all the continents once fit together as one big continent called Pangaea (all land).
There were four pieces of evidence used: 1) the fit of the continents, especially So. America and Africa, 2) rock structure due to glaciation, 3) fossils such as Mesosaurus and Glossopteris, 4) ancient climates such as glacial history where it is now tropical.
The crust and the upper mantle
The lower part of the upper mantle.
The lithosphere (crust and upper mantle)
1) The fit of the continents. People argued that the shorelines
are constantly eroding. This was defeated by showing that the continents fit at the
continental shelf under water not at the shoreline.
2) Fossil evidence. People argued that there was a land bridge which enabled the Mesosaurus to cross the ocean. This was defeated due to lack of evidence of a land bridge in the middle of the Atlantic Ocean.
Plate boundaries are locations in which two or more plates meet. Depending on the type of plate (oceanic or continental) may things can occur such as mountain building to subduction and volcanoes.
Diverging, converging, transform - be sure to review your notes from class on this****
Deep earthquakes occur where at subduction boundaries like north of the Aleutian trench. As the crust is getting pulled down further, causing friction at a deeper depth.
Converging boundary between oceanic and continental crust
As the distance from the spreading center increases, the age of the rock also increases.
New crust is forming at the ridges in the ocean and depositing the older crust on land.
Continental crust is less dense than oceanic crust. When a lower density continental plate converges with a high density oceanic plate the higher density oceanic plate will subduct (go under) the continental plate.
At spreading centers new crust is being produced, and at the trenches the older crust is being recycled through subduction.
At the mid-ocean ridges.
Rift. Yes, in rift valleys such as in East Africa.