1.1.5: More coastal processes Flashcards
Sub aerial weathering
is where
above
Physical and mechanical weathering
Breaks off rocks of varying sizes which fall to the foot of the cliff and protect it from erosion
2 types of physical and mechanical weathering
- freeze thaw
- seawater gets in cracks
Freeze thaw weathering
(wetting and drying)
water layer,
expansion and contraction of minerals
Where does freeze thaw occur
macrotidal environments
What is freeze thaw most effective on
clay
Sea water gets in cracks weathering
cracks in rocks
evaporates
crystals left behind which grow
exert pressure on the rock causing it to break apart
3 types of weathering
physical/mechanical
chemical
biotic
5 types of chemical weathering
solution hydration hydrolysis oxidation chelation
Solution
chemical weathering
solubility of minerals
depends on temp and acidity of the water
Hydration
chemical weathering
Minerals absorb water which weakens their structure
Hydrolysis
chemical weathering
Reaction between minerals and water
related to hydrogen ion conc in water
affects granite
Oxidation
chemical weathering
Adding or removing O2
often affects rocks with a high iron content
common under water logged conditions
Chelation
chemical weathering
Organic acids are produced by plant roots and decaying organic matter = weathering
Biotic weathering
Caused by plant roots or animals burrowing
can cause softer rocks to break apart