types of plate margin Flashcards
1
Q
What is a collision (destructive) margin?
A
Where two continental plates move together
2
Q
What is a constructive margin?
A
Where two plates move away from each other
3
Q
What is a conservative margin?
A
Where two plates slide alongside each other
4
Q
What happens in subduction?
A
- Convection currents in the mantle cause the plates to move together.
- The denser oceanic crust sinks under the lighter continental crust.
- Great pressure is exerted.
- The oceanic crust is destroyed as it melts to form magma.
5
Q
How do volcanoes form at constructive plate margins?
A
- Usually happens under the ocean
- As the oceanic plates pull away from each other, cracks and fractures form between the plates where there is no solid crust
- Magma forces it’s way into the cracks and makes its way to the surface
- In this way new land is formed as the plates gradually pull apart
6
Q
How to earthquakes occur at conservative plate margin?
A
- The two plates are moving in a similar (though not the same) direction, at slightly different angles and speeds
- Therefore, they tend to get stuck
- Eventually, the build up of pressure causes them to be released
- This sudden release of pressure causes an earthquake
7
Q
What is happening to the crust at a conservative plate margin?
A
It is being neither destroyed nor made
8
Q
Where are there volcanoes?
A
+ Destructive = composite volcanoes
+ Constructive = shield volcanoes
+ Conservative = there is no source of magma so volcanoes are absent
9
Q
What is a destructive margin?
A
Where one plate sinks under another (subduction)
