Plate Movement and convergent plate boundaries Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

How many layers make up the structure of the Earth

A

Inner core - solid
Outer core - liquid
Mantle - molten rock
Crust - solid rock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Outline some AO1 knowledge about oceanic crust.

A

Oceanic:
Dense
subduction can occur (can be destroyed) younger (because it can be renewed)
BASALT
Faster moving.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the names of the sections that make up the Crust/ mantle (as these two layers are not completely separate)

A

Lithosphere - crust + little bit of mantle (80-90 km thick)
Asthenosphere - very viscous.
Mesosphere - section below Asthenosphere in the mantle. Viscous.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give some AO1 knowledge about continental crust:

A

Thicker
Less dense
CAN’T be subducted
CAN’T be renewed/destroyed
GRANITE / SEDIMENTARY
Slow moving.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What 3 ways do plates move?

A

Convection currents.
(Friction between lithosphere and asthenosphere pulls tectonic plates)

Ridge push AKA Gravitational sliding.

Slab pull.

They all work together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain ridge push / gravitational sliding?

A

Driving force for plate movement,

Occurs at mid-oceanic ridges

rigid lithosphere sliding down hot, raised asthenosphere underneath mid-ocean ridges - push is caused by gravity.
Gravitational force occurs because ridge = higher elevation than the rest of the ocean floor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is slab pull?

A

Plate cools as it moves away from mid ocean ridge (cool and dense so subducts).

Pulls rest of slab into mantle below like a conveyor belt.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the benioff zone?

A

The area where the subducting plate and the squished upper plate meet. There is LOTS OF FRICTION here.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a convergent plate boundary

A

Two plates moving towards each other. One subducts beneath the other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why do volcanoes occur at subduction zones?
Give an example

A

compression of continental crust (fold mountains, some of which will be volcanoes.)
melting plate underneath creates volcanoes.
This forms a volcanic arc.

The ANDES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the andes a good example of?

A

A volcanic arc.
occurring at an oceanic and continental convergent plate boundary.

the andes include volcanoes like Nevada Del Ruiz and have the Nazca oceanic plate and the South American continental plate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the difference between an oceanic : continental convergent plate boundary and a Oceanic : Oceanic convergent plate boundary?

A

Get and island arc chain (e.g Mt Peleé) instead of a volcanic arc.

E.G - the Caribbean (Mt. Peleé)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Continental : continental collision boundaries.
Example:
What happens at convergent plate boundaries in this situation?

A

Himalayas
no volcanoes because no subduction.
Occur when oceanic lithosphere has fully subducted so ocean disappears and continental plates meet.
Accretionary wedge (ocean floor sediments compress into fold mountains) have bridged the gap between the plates creating the Himalayas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly