Restless Earth- Exam Focus

1. Two characteristics of the mantle:

• Solid
• Upper mantle is partially molten

2.Which best describes the crust?
A. A thin layer of basalt on the Earths surface
B. A hot molten area of iron and nickel
C. A solid layer that is made up of granitic and basaltic rocks

3. What is a hotspot?
A hotspot is an area of rising plumes of magma in the asthenosphere which create volcanoes in the crust. It generally creates a trail of volcanoes all in one area

4. Explain why Tectonic plates move
The crust and upper mantle are split into many plates which move because of convection currents in the lower mantle. These are caused by the heat from the radioactive decay of the core, the plates move a few centimetres every year. Plates meet at boundaries where they either collide, move apart of slide passed eachother. These movements create Volcanoes and Earthquakes. These theories were proposed by Alfred Wegener. 

5. Describe the pattern of plate boundaries.
Earthquakes and Volcanoes are usually concentrated into a one area of along the same plate boundary. The crust is split into many different plates, the destructive plate boundaries are found where oceanic crust meets continental crust, for example, the NAZCA plate and the South American. These kinds of collisions normally create fold mountains and…