Weathering

Question 1

Biological

Answer 1

Plant or root pressure

Organic acids

Question 2

Wetting and Drying

Answer 2

(Action of water)
Porous rocks are soaked
Drying causes minerals to precipitate
Causes desert pavement/ tafoni

Question 3

Crystal growth

Answer 3

(action of water and heat)
saline solution seeks into cracks
Salt crystals left behind
Crystals expand after heating

Question 4

Hydration

Answer 4

(action of water)
Water forms weak bonds with mineral ions
Mineral ions can expand
Lead to disintegration of rocks

Question 5

Oxidation

Answer 5

(action of air and water)
Metal minerals in rocks react with O2
Produces rust

Question 6

Solution / Hydrolysis

Answer 6

(Action of water)
Hydrogen ions increase acidity of water
Create organic acids

Question 7

Insolation

Answer 7

(action of temperature change)
Variation in temp. causes rock to expand and contract
Breaks apart

Question 8

Exfoliation

Answer 8

(action of temp. change)
Outer layer of rock heated
Causing expansion
Temperature drops 
Causing contraction
Sheets of rock 'peel'

Question 9

Granular disintegration

Answer 9

(action of temp. change)
Repeated heating and cooling
Dark colour = absorbs more light = contracts faster
Light colour = absorbs less light = contracts slower
Breaks apart

Question 10

Block disintegration

Answer 10

When rocks are jointed
Split along joints
Expansion and contraction over time

Question 11

Salt Weathering

Answer 11

(action of water and heat)
Saline solution moves into cracks
Evaporated
Leaving salt crystals
Breaks rock apart when expands

Question 12

Freeze thaw weathering

Answer 12

(Action and temp. changes)
Water enters crack in day 
At night water freezes
Water expands by 9% becoming ice
Breaks rock