Mechanical/physical weathering

Question 1

What does mechanical/physical weathering depend on?

Answer 1

The nature of the climate.

In latitudes where temperature fluctuate above and below freezing.

Question 2

What is freeze-thaw weathering?

Answer 2

Water enters the crack in the rocks freezes as temperatures remain below 0’C.
As it freezes the water expands by almost 10% meaning the ice occupies more space and so exerts pressure of the surrounding rock.
The process repeats and continues.
The crack widens and eventually pieces of rock break off.

Question 3

Define mechanical weathering.

Answer 3

The physical breakdown of rock by environmental factors.

Question 4

Define frost shattering.

Answer 4

Is the presence of large amounts of sea water and the tendency for coastal rocks to be severely cracked by the process of erosion.
Coastal locations tend to be warmer than inland localities, reducing likelihood of frosts.

Question 5

Define salt crystallisation.

Answer 5

Its active at the coast due to the prescence of saltwater.
In tidal/splash zone, salt water is readily available and evaporation leads to the formation of salt crystals.
As they grow, they exert pressure within the rock, causing it to gradually break apart.

Question 6

Define wetting and drying.

Answer 6

Active in the tidal/splash zone.
Where clays/shales are present and prone to expansion and contraction associated with wetting and drying.
This forms cracks, weakening the rock and encourages erosion.