PLATE BOUNDRIES

Question 1

What is the direction of movement in a divergent plate boundary?

Answer 1

Moving apart from one another

Question 2

What crusts are involved in a divergent plate boundary?

Answer 2

Oceanic and oceanic

Question 3

What are the major landforms that result in divergent plate boundaries?

Answer 3

Oceanic ridges and islands

Question 4

How do volcanoes form in divergent plate boundaries

Answer 4

When magma escapes and gets pushed upwards from the mantle

Question 5

In what direction do convergent plate boundaries move ?

Answer 5

They collide into each other but subduction occurs (one plate goes under the other)

Question 6

What’s a hotspot?

Answer 6

A place in the Center of a plate where magma rises causing the lithosphere to melt and therefor pushing magma to the crust forming volcanoes

Question 7

What crusts are involved in convergent plate boundaries?

Answer 7

Oceanic and continental

Question 8

What is the major landform from the movement of convergent plate boundaries?

Answer 8

Mountains

Question 9

Name two plates on a divergent plate boundary

Answer 9

African and South American plate

Question 10

Are the earthquakes in convergent plate boundaries larger or smaller than divergent plate boundaries?

Answer 10

Larger

Question 11

In what direction do collision plate boundaries move?

Answer 11

Towards each other and they collide

Question 12

What types of crust are involved in collision plate boundaries?

Answer 12

Continental and continental

Question 13

What is the major landform from collision plate boundaries and why?

Answer 13

Fold mountains as the plates are forced upwards when they collide

Question 14

What two crusts are present at a destructive plate margin?

Answer 14

Oceanic and continental

Question 15

What is a real life example of a destructive margin?

Answer 15

Nazca crust and the South American plate
Peru- chile trench
The Andes as fold mountains

Question 16

Give an explanation of a destructive boundary

Answer 16

• plates collide at a destructive boundary
• younger, denser oceanic crust sinks as it is forced beneath older permanent continental crust
• as the plate is submerged friction melts the oceanic crust and this contributed to the magma chamber as it melts and creates pressure so a volcano can form also, due to the immense pressure exerted, earthquakes can be triggered in the Benioff zone
• fold mountains occur as the collision occurs and the plate buckles upwards
• obduction could occur resulting in a mid ocean ridge
• ocean trench is formed

Question 17

What crusts are present at a continental oceanic collision?

Answer 17

Oceanic and continental

Question 18

When labelling a diagram of a destructive boundary, what key aspects should be included?

Answer 18

• arrows showing direction of play movement
• two plates, the oceanic plate being sub-ducted beneath the continental
• earthquake and Benioff zone
• convection currents in mantle
• magma chamber, composet cone and fold mountains
• a ocean trench with subduction zone

Question 19

What is an example of a real life continental- oceanic collision boundary?

Answer 19

Nazca crust and South American plate

Question 20

Give an explanation of a continental-oceanic collision boundary

Answer 20

• As the plates meet the denser lithosphere is forced down under the continental lithosphere and it descends by the process of subduction
• this can be made clear by a ocean trench at the surface
• as the oceanic plate descends, shallow focus earthquakes can be triggered by friction in the Benioff zone
• as subduction continues, sediment accumulated on the ocean floor is scraped off and forced onto the continental plate, this is called obduction this contributes to the continents size
• continual plate buckles forming fold mountains
• sea water enters the mantle, causing water to be liberated lowering the mantles melting point which produces magma which rises and can be erupted in the surface

Question 21

What two crusts are involved in oceanic-oceanic collision?

Answer 21

Both oceanic crusts

Question 22

When labelling a diagram of oceanic-oceanic collision, what key aspects would you label?

Answer 22

• direction of plate movement
• understand it’s underwater
• trench thought one side and a island arc with a volcano
• one overriding plate and one subducting
• magma rising from the asthenosphere, through the lithosphere to the surface

Question 23

What is a real life example of oceanic-oceanic collision?

Answer 23

The South American plate moving increasingly westwards until it meets the Caribbean plate

Question 24

Give and explanation of a oceanic-oceanic collision boundary

Answer 24

When two oceanic plates collide one oceanic plate is eventually subducted under the other.
As the subducting plate descends into the mantle where it is being gradually heated a benioff zone is formed. This benioff zone is a zone of shallow,intermediate and deep focused earthquakes. Some deep focused earthquakes that occur at ocean ocean- collision boundaries
As the subducted plate descends into the mantle it is gradually heated allowing the formation of magma.
The magma that forms is andesitic in composition and begins to form when the subducted plate reaches a depth of 100 kilometres
This andesitic magma is formed from the partial melting of the asthenosphere just above the subduction zone.
This partial melting of the subducting plate is due to the loss of water as it descends into the mantle. The andesitic magma is now less dense than the surrounding material so it rises through the crust and erupts to form an arc of volcanoes called an island arc.

Question 25

What crusts are involved in continental-continental collision (collision boundary)?

Answer 25

Continental and continental

Question 26

What key aspects would you label on a diagram?

Answer 26

• plate direction
• fold mountains
• continental crust
• one side subducting
• separate diagram with geosynclines and anticlines and synclines
• depression
• lithosphere and asthenosphere

Question 27

What is a real life example of a continental-continental collision boundary?

Answer 27

Himalayas, Indian plate and Eurasian plate
Began moving 50 million years ago and is still moving
225 million years ago after Pangea broke up India began to migrate to wars the Asian continent at 9-16 cm per year
Continents then collided and the ocean was closed

Question 28

Explain what happens at a continental-continental collision boundary

Answer 28

-ancient rivers once flowed in to ancient seas, geosynclines which over time, layers of sediment built up and compressed in the geosyncline
-as the plates move together, the sediment begins to buckle upwards as it is compressed by the moving plates
When the plates collide a fold mountain has been created with anticlines and sync lines as neither crusts can be subducted due to their low density