Convection Currents Flashcards
1
Q
What are convection currents?
A
rising of warm magma and falling of cool magma in the Earth’s mantle causing the plates on the surface to move
2
Q
What are the stages of convection currents moving tectonic plates?
A
- heat from the core is conducted to the mantle
- warm magma becomes less dense and rises
- at the crust, the magma spreads dragging the plates apart
- as the magma cools, it’s becomes less dense and sinks, dragging the plate above with it so it subducts below the continental plate
3
Q
What 3 types movement of plates does this cause?
A
- destructive
- constructive
- conservative
4
Q
Describe a destructive plate boundary with two continental plates.
A
- plates move towards each other
- large earthquakes
- huge fold mountains
5
Q
Describe constructive plate boundaries.
A
- plates move away from each other
- oceanic or continental
- small shallow earthquakes
- large shield volcanoes
- oceanic ridges for made of new crust
- whole volcanic islands may form
6
Q
Describe a destructive plate boundary with a oceanic and continental plate.
A
- plates move towards each other
- oceanic subducted as most dense plate
- large earthquakes
- water, dead sea creatures and sediment subduct with the oceanic plate and are heated by the magma forming CO2, then rises through cracks because of the pressure and creates composite volcanoes
- deep sea ocean trenches, continental volcanic arcs, volcanic island arcs
7
Q
Describe a conservative plate boundary.
A
- plates move side by side
- oceanic and continental
- large earthquakes
- occurs along ocean ridges