Plate tectonic landforms

Question 1

2 ways Fold mountains formed

Answer 1

Mountains created by uplifting of crumbling rock layers of 2 convergent plate boundaries
Destructive plate boundaries

Question 2

Rift valley def

Answer 2

Steep sided valley formed by the downward displacement of a block between faults e.g. E.African rift valley

Question 3

4 stages of Rift valley formation

Answer 3

1) Divergent plate boundary
2) When tensional forces are great enough a central block collapses forming a graben
3) This forms a valley which widens to become a large basin
4) The basin accumulates sediment from the rift walls and its proximity

Question 4

Ocean ridge def

Answer 4

A large continuous range of submarine mountains formed at constructive margins

Question 5

2 Oceans ridge formation processes

Answer 5

1) Ridge -push is when the weight of the ridge pushes the rest of tectonic plate from it
2) Slab-push is the weight of the tectonic plate being subducted

Question 6

Deep sea trenches def

Answer 6

Steep sided depression in oceanic crust e.g.

Question 7

Formation of sea trench

Answer 7

2 converging plates meet the denser subducts creating a trench + outer trench swell

Question 8

Volcanic island arcs definition

Answer 8

Curved chain of volcanic islands occurring over the the overriding plate of a subduction e.g. Mariouna islands

Question 9

Volcanic island arc formation

Answer 9

As the oceanic plate is subducted the greater pressures lower the melting point allowing it to melt in the mantle underneath the overriding plate
This magma can ascend to form an arc of volcanoes
These volcanoes pile up until a submarine volcano breaches the water surface

Question 10

Hot spot definition

Answer 10

Volcanic areas fed by underlying mantle that are anomalously hot e.g. Hawaii

Question 11

2 Theories for got spots

Answer 11

Hot mantle plumes rise as thermal diapirs from the core mantle boundary
Lithosphere extension permits passive rising of magma from shallow depths