Weathering and mass movement

Question 1

Why do cliffs collapse?

Answer 1

Due to weathering
(the wearing away or decaying of rocks due to actions of weather, plants and animals)

Question 2

Define weathering

Answer 2

The wearing away or decaying of rocks due to actions of the weather, plants and animals

Question 3

Name the three types of weathering

Answer 3

Physical

Chemical

Biological

Question 4

Name an example of physical weathering.

Answer 4

**Freeze-thaw **weathering

Question 5

Describe freeze-thaw weathering

Answer 5

1. precipitation collects in cracks in the cliff
2. At night, the temperature decreases, making the water freeze. This causes the crack to expand
3. In the day, the temperature rises, this causes the ice to thaw and for the water to seep deeper in the cliff
4. Repeated freezing and thawing eventually causes the rock fragment to break off. (they collect as scree at the botom of the cliff)

Question 6

Name an example of chemical weathering

Answer 6

Carbonation

Question 7

Describe the chemical weathering process of carbonation

Answer 7

1. Rainwater absorbs the Carbon dioxide in the air and becomes slightly acidic
2. The water has a chemical reaction with an alkaline rock (e.g. limestone) and this causes the rock to slowly dissolve.

Question 8

What is biological weathering

Answer 8

Wearing away of rocks caused by plants and animals

Question 9

Describe biological weathering

Answer 9

Plant roots grow in cracks in the cliff and animals (e.g. rabbits) burrow into weak rocks.

Both of these biological actions cause rock fragments to break off.

Question 10

What is mass movement

Answer 10

The downwards sliding of weathered material and rocks under the influence of gravity

Question 11

Mass movement is a result of ______________

Answer 11

Weathering

Question 12

Name the four types of mass movement

Answer 12

Rockfall

Landslide

Mudflow

Rotational slip

Question 13

Describe rock fall

Answer 13

The rocks break off and fall down the cliff face as a result of freeze-thaw weathering

Question 14

Describe the landslide mass movement

Answer 14

blocks of detatched rocks slide downhill.

Question 15

Describe the mudflow mass movement

Answer 15

Saturated soil (mud) and rock debris flow downhill.

Question 16

Desrcibe rotational slip mass movement

Answer 16

The slumping of saturated soil and rock debris along a curved slip plane.