The Earth's Layers + Types Of Plate Boundaries

Question 1

What are the four layers in which the earth is made up of?

Answer 1

The earth is made up of the inner core, outer core, mantle, crust.

Question 2

What are the features of the crust?

Answer 2

Some features of the crust: (3)
Varies in thickness, it is the thinnest part of the earth
Around 5-10km beneath the ocean
Made up of several large plates

Question 3

What are the features of the mantle?

Answer 3

Some features of the mantle: (3)

Widest Layer of the earth - 2900km thick.
The heat and pressure means the rock is always in a liquid state. Suitable for convection currents.

Question 4

What are the features of the inner core and outer core?

Answer 4

Some features of inner core and outer core are its: (3)

Hottest part of the earth - 5500°C
Mostly made up of iron and nickel
4x denser than the crust

Inner core is solid
Outer core is liquid

Question 5

Explain in five steps how convection currents work?

Answer 5

1. The Radioactive decay of some of the elements in the mantle generate a lot of heat
2. This heat causes magma in the lower parts of the mantle to heat up and become less dense and slowly rise
3. As it moves towards the top, it cools down and therefore becomes more dense and slowly sinks.
4. These circular motions of the semi-molten rock (magma) are called convection currents.
5. Convection currents create drag on the base of the tectonic plates and this causes them to move.

Question 6

What is the rate of continental drift per year?

Answer 6

The rate of continental drift per year is 2.5cm.

Question 7

There are four different types of plate margin / boundary. What are they?

Answer 7

The four different types of plate margin are:

1. Destructive Plate Margin
2. Constructive Plate Margin
3. Conservative Plate Margin
4. Collision Plate Margin

Question 8

Describe the Destructive Plate Margin:

Give an example of this boundary.

Answer 8

Destructive Plate Margin occurs when an oceanic and continental plate move toward each other.

If an oceanic plate converges with a continental plate, the denser oceanic plate is forced under the continental plate, creating a subduction zone. The friction between these plates causes the subducted plate to melt and become molten magma. This magma then forces its way up to the surface, through the weaker points of the plate above to form a volcano. This margin is also responsible for devastating earthquakes.

Example of a destructive plate margin is: The Nazca plate is being subducted under the South American Plate

Question 9

Describe the Conservative Plate Margin:

Give an example of this boundary.

Answer 9

Conservative Plate Margin occurs when two plates slide past each other in opposite directions or in the same direction at different speeds. This can cause friction between the plates causing pressure to build up, this energy is then released in the form of earthquakes.

Example of a conservative plate margin is: San Andreas Fault, USA

Question 10

Describe the Constructive Plate Margin:

Give an example of this boundary.

Answer 10

Constructive Plate Margins occur when two plates are moving apart, which causes the magma to move up through the gap and form new land. Safe to visit.

Example of a constructive plate margin is: The Mid-Atlantic Ridge - Iceland

Question 11

Describe the Collision Plate Margin:

Give an example of this boundary.

Answer 11

Collison Plate Margin occurs when two continental plates move towards each other.

Since both plates are similar density, neither is subducted; instead, they collide and push upwards to form mountain ranges.

Example of a collision plate margin is: The Himalayas