PLATE BOUNDARIES

Question 1

What are the three main types of plate boundaries?

Answer 1

1) Divergent plate boundaries (divide)
2) Convergent plate boundaries (collide)
3) Transform plate boundaries

Question 2

What do plates do at divergent/constructive plate boundaries?

Answer 2

Divide/Separate

Question 3

Why do plates divide at divergent plate boundaries?

Answer 3

Convection currents in the mantle beneath them are moving in opposite directions therefore dragging plates apart.

Question 4

Example of 2 plates that are dividing:

Answer 4

North American and Eurasian plates.

Question 5

When plates are pulling apart, what happens to the crust exactly?

Answer 5

It tears and cracks/fissures open up in the crust.

Question 6

In the case of the North American and Eurasian plates where does the crust tear?

Answer 6

In the middle of the Atlantic Ocean under the sea.

Question 7

What happens when a tear in the earth’s crust occurs?

Answer 7

Magma from the mantle rises through the gap.

Question 8

When magma rises through the fissures, what occurs after?

Answer 8

The magma cools quickly and hardens , creating basalt.

Question 9

What’s the term used to describe plates separating under the sea and creating new sea floor?

Answer 9

Sea floor spreading.

Question 10

Over time due to the process of sea floor spreading, what can occur?

Answer 10

In and around 130my an underwater mountain range can be created.

Question 11

When the underwater mountain range occasionally rises above the sea what is it then know as?

Answer 11

Volcanic islands.

Question 12

The underwater mountain range is known as a …

Answer 12

Mid ocean ridge

Question 13

Concerning the Eurasian and North American plates, what is their mid-ocean ridge called?

Answer 13

Mid-Atlantic Ridge

Question 14

For how long does the Mid-Atlantic Ridge run for?

Answer 14

15,000 kms

Question 15

What’s an example of an island along the Mid-Atlantic Ridge?

Answer 15

Iceland.

Question 16

How many active volcanoes does Iceland have?

Answer 16

130.

Question 17

What do plates do at convergent plate boundaries?

Answer 17

Collide.

Question 18

Why do plates collide at convergent plate boundaries?

Answer 18

As the convection currents in the mantle beneath them are moving towards each other, pulling the plates together.

Question 19

What are the different types of convergent plate boundaries?

Answer 19

1) Oceanic-oceanic convergence (two oceanic plates collide)
2) Oceanic-continental convergence (oceanic and continental plates collide)
3) Continental-continental convergence (two continental plates collide).

Question 20

What is an example of two oceanic plates colliding?

Answer 20

The Pacific and Philippine plates.

Question 21

Oceanic-oceanic convergence leads to the formation of what?

Answer 21

Ocean trenches and volcanic island arcs.

Question 22

Example of a ocean trench:

Answer 22

The Marianas trench

Question 23

How deep is the Marianas trench?

Answer 23

11km

Question 24

What is an example of an oceanic and continental plate colliding?

Answer 24

The Nazca and South American plates.

Question 25

Oceanic-continental convergence leads to the formation of:

Answer 25

Fold mountains and volcanic activity.

Question 26

When the oceanic plate and continental plate collide what process occurs and describe it.

Answer 26

Subduction - the heavier plate (oceanic) bends and sinks beneath the lighter plate (continental)

Question 27

Where does subduction occur at?

Answer 27

At a subduction zone.

Question 28

The collision of the oceanic and continental plate cause the continental plate to...

Answer 28

Buckle upwards which forms a fold mountain range e.g. the Andes.

Question 29

When the oceanic plate subducts down into the mantle what happens?

Answer 29

The plate melts due to the high heat of the mantle and it's destroyed.

Question 30

When the subducted plate is destroyed what occurs?

Answer 30

Extra magma is created in the mantle. Some of magma may spill out through the overlying continental plate resulting in volcanic activity.

Question 31

Are the Andes volcanically active?

Answer 31

Yes.

Question 32

Give an example of a volcanically active mountain in the Andes.

Answer 32

Cotopaxi.

Question 33

What is an example of two continental plates colliding?

Answer 33

Eurasian and Indo-Australian plates.

Question 34

What does continental-continental convergence lead to?

Answer 34

Formation of fold mountains e.g. the Himalayas.

Question 35

What's the highest peak of the Himalayas and what's the exact figure?

Answer 35

Mount Everest (8848m)

Question 36

Does any subduction occur during continental-continental convergence? Why?

Answer 36

Little to no subduction occurs as the plates are similar in weight and thickness.

Question 37

Since plates don't move down in c-c convergence what does happen?

Answer 37

An uplift where two plates buckle upwards.

Question 38

Are the Himalayas volcanically active?

Answer 38

No.

Question 39

What do plates do at transform plate boundaries?

Answer 39

Slide.

Question 40

Which way do plates slide in at transform boundaries and what speed do they move in?

Answer 40

The can either move in the same or opposite direction but at different speeds.

Question 41

Example of two plates sliding in opposite direction:

Answer 41

North American and Caribbean plates.

Question 42

Example of two plates sliding in the same direction:

Answer 42

North American and Pacific plates.

Question 43

The line that the plates slide along is called a...

Answer 43

Transform fault line.

Question 44

Give an example of a transform fault line:

Answer 44

The San Andreas Fault.

Question 45

How long does the San Andreas Fault run for?

Answer 45

1,300kms

Question 46

In the San Andreas Fault case which plate moves faster?

Answer 46

The Pacific plate moves faster (5cm per year) than the North American plate (1cm per year).

Question 47

Is the movement of sliding plates smooth?

Answer 47

No, the plates grind against each other.

Question 48

When the plates grind against each other, what happens?

Answer 48

They get stuck and lock together for decades with pressure building up over time.

Question 49

When the sliding plates jolt forward again what happens?

Answer 49

The pressure is released and a violent earthquake occurs.