Weathering

Question 1

What is Denudation?

Answer 1

Rocks on the earths surface are constantly being worn down by a number of processes known as DENUDATION

Question 2

What is weathering?

Answer 2

Weathering is the process that physically changes solid rock into smaller pieces or sediments

Question 3

How many types of weathering are there? Name them

Answer 3

There are three types of weathering

1. Mechanical
2. Chemical
3. Biological

Question 4

What is Erosion?

Answer 4

Erosion is the process that breaks down and moves sediment away from the original positions

Question 5

What is Mechanical weathering?

Answer 5

Mechanical weathering is the physical breaking down of rocks into smaller pieces

Question 6

What is the most common type of mechanical weathering? Explain the process

Answer 6

The most common type of mechanical weathering is freeze-thaw action

Process:
1. Water gathers in the cracks in rocks during the day

2. At night if the temperature drops below 0 degrees the water freezes to become ice

This puts pressure on the rock as the ice expands by up to 10%.
The next day the water thaws and melts again

3. Repeated freezing and thawing results in the rock becoming weak and breaking into smaller pieces. These pieces roll down in the slope and gather, they are known as scree

Question 7

What is chemical weathering?

Answer 7

Chemical weathering is caused by chemical changes when rock is dissolved or decays

Question 8

What is carbonation? Explain the process.

Answer 8

Carbonation is an example of chemical weathering

Process:
1. As rainwater falls and passes through the air it dissolves carbon dioxide.

2. Carbon dioxide mixes with the the rainwater to form a weak carbonic acid
3. Limestone in the ground contains calcium carbonate. When the weak carbonic acid in rainwater falls onto limestone a chemical reaction takes place
4. The calcium carbonate in the limestone begins to disolve this process is known as CARBONATION
5. Limestone is permeable rock meaning rainwater can easily pass through it. It has vertical cracks which are called joints and horizontal is bedding planes

Question 9

What is a karst landscape?

Answer 9

Karst landscapes are areas of land made up of Limestone

Question 10

Surface features - Limestone pavement

Answer 10

The bare, rocky karst surface is called a limestone pavement The pavement is made up of Clints and grikes

Question 11

What are clints and grikes?

Answer 11

Clints are the slabs of rock on the surface that separate the grikes

Grikes are deep grooves in the pavement. They become weathered widened and deepened by carbonation

Question 12

What is a swallow hole?

Answer 12

A swallow hole is when a river enters a karst landscape it can disappear underground through grikes the grikes become enlarged forming big vertical holes known as swallow holes