The restless Earth summary

Restless Earth

• Crust: outer layer of the earth
• Plate: a section of the earth's crust
• Plate Margin: the boundary where two plates meet 
• Mantle: dense mostly solid layer between outer core and crust 
• Convection Currents: the circular currents of heat in the mantle

Oceanic Crust:

• Newer- most less than 200 million years old
• Denser
• Can sink
• Can be renewed and destroyed

Continental Crust:

• Older- most over 1500 million years old
• Less dense
• Cannot sink
• Cannot be renewed or destroyed

Destructive plate margins: 

• Convection currents in mantle cause plates move together
• Denser oceanic crust sinks under continental crust (subduction)
• Great pressure exerted and oceanic crust is destroyed to form magma
• Two continental plates meet each other, collide rather than sinking beneath each other. The collision boundary is a different type of destructive margin. 
• Severe earthquakes and violent volcanic eruptions

Constructive plate margins:

• When plates move apart constructive plate boundary results 
• Occurs under oceans; as plates move apart cracks form between plates and magma forces way into cracks and makes its way to…