Weathering And Mass Movement

Question 1

What does weathering mean?

Answer 1

The breakdown of rocks by physical or chemical changes in situ (one place)

Question 2

Name the two types of mechanical weathering.

Answer 2

Freeze-thaw weathering and salt weathering

Question 3

What is freeze-thaw weathering?

Answer 3

Water freezing and thawing in a crack causes expansion and contraction of the rock. This puts pressure on the rock which eventually causes the rock to disintegrate.

Question 4

What is salt weathering?

Answer 4

Seawater contains salt. When the wager evaporates it leaves behind salt crystals. In cracks and holes these salt crystals grow and expand. This puts pressure on rocks and flakes may eventually break off.

Question 5

Name a type of chemical weathering.

Answer 5

Carbonation

Question 6

What is carbonation?

Answer 6

Rainwater is slightly acidic. Contact with alkaline rocks such as chalk and limestone produces a chemical reaction causing the rocks to slowly dissolve

Question 7

What does mass movement mean?

Answer 7

The downslope movement of rock, soil or mud under the influence of gravity

Question 8

Name three types of mass movement.

Answer 8

Slides, rock falls and slumping

Question 9

What is a slide?

Answer 9

Occurs after periods of heavy rain when loose surface material becomes saturated and the extra weight causes the material to become unstable and move rapidly downhill, sometimes in an almost fluid state

Question 10

What is rockfall?

Answer 10

They occur on bare rock surfaces that are well jointed and prone to freeze-thaw weathering

Question 11

What is slumping?

Answer 11

Rapid mass movement which involves a whole segment of the cliff moving down-slope along a saturated shear-plane or line of weakness