Other margins Flashcards
1
Q
Destructive Oceanic to Oceanic
A
- heavier plate subducts, leaving an ocean trench
- fold mountains occur
- Built-up pressure causes underwater volcanoes to bust through oceanic plate
- lava cools, forms new land called volc island arcs
- aleutian islands alaska, marianas islands SE of japan
1
Q
Destructive Continental on Continental
A
- both plates not as dense as oceanic so lots of pressure builds
- ancient oceanic crust subducted slightly, but no subduction of continental crust
- pile-up of continental crust on top of lithosphere due to pressure between plates
- fold mountains formed from plies of continental crust
2
Q
Constructive Continental to Continental
A
- any land in the middle of the separation is forced apart, forming a rift valley
- volcanoes form where the magma rises
- eventually, gap will fill with water and separate from main island
- lifted areas of rocks known as horsts, valley itself known as a graben
3
Q
Conservative plate
A
- paralell plates move in diff directions / diff speeds
- no plates destroyed so no landforms
- when they move, lots pressure built up = eq
- on oceanic crust, can displace a lot of water. - on continental crust, fault lines can occur where the ground is cracked by the movement
