Unit Four - Plate Boundaries

Question 1

How does the mid - ocean ridges and rift valleys work (4)?

Answer 1

1. Hot mantle rocks are rising below it, pushing the earth’s crust/ridge up
2. As those rocks get closer to the surface they melt
3. As plates separate, magma rises and erupt on the central rift valley floor
4. This produces enormous volcanic eruptions of basalt.

Question 2

What is the Convergent Plate Boundary?

Answer 2

Plates move TOWARDS each other

Question 3

What is the Transform Plate Boundary?

Answer 3

Plates slide horizontally PAST one another.

Question 4

What is a mid - ocean ridge (6)?

Answer 4

1. Like an underwater mountain
2. The ridge is found in the center of the ocean
3. Divergent Boundary
4. Where the sea - floor spreading starts to take place
5. As plates separate, new ocean floor is created
6. The closer a piece of the rock is to the ridge, the younger it is.

Question 5

What happens as a result of transform plate boundary (3)?

Answer 5

1. Earthquakes
2. Faults
3. Dislocation of Rocks

Question 6

What is the theory of plate tectonics? (3)

Answer 6

1. The solid lithosphere
2. Consists of a series of plates
3. Floats on the partially molten section of the mantle

Question 7

What happens as a result of convergent plates (4)?

Answer 7

1. Mountains
2. Earthquakes
3. Volcanic activity
4. Trenches

Question 8

What happens as a result of divergent plates (6)?

Answer 8

1. New Oceanic Crust
2. Volcanic Activity
3. Shallow Earthquakes
4. Ocean ridges
5. Deep Rift Valleys
6. Convergent Plates

Question 9

How do different plate boundaries interact and help form a volcano? (6)

Answer 9

1. The oceanic crust moves towards a continental crust
   (Due to diverging plates and MAGNETIC ORIENTATION)
2. Since the oceanic crust is more dense than the continental crust, it bends down and subducts.
3. This creates a mountain.
4. When the oceanic crust bends down, it eventually reaches the asthenosphere and melts into magma.
5. The gases rises up from the magma and wants to escape.
6. Gases and pressure builds up in the mountain,causing it to explode and lava seeps out

CREATING A VOLCANO!

Question 10

What crust is more dense (and what proves it)? (3)

Answer 10

1. Oceanic crust is more dense than the continental crust
2. It sinks underwater
3. Subducts under the continental crust at a convergent boundary

Question 11

What is the Divergent Plate Boundary?

Answer 11

Plates move AWAY from each other.

Question 12

What is a rift valley? (3)

Answer 12

1. Caused by Seafloor Spreading
2. An enormous fracture in the seafloor
3. Progressively widens.