Weathering

Question 1

what is weathering

Answer 1

the breakdown of rock at/near ground surface when exposed to air, moisture or organic matter

Question 2

where does weathering happen

Answer 2

in situ (in place)

Question 3

how is weathering different to erosion

Answer 3

weathering is where rock is changed/broken in place , this becomes erosion if the weathered rock moves

Question 4

what is physical weathering

Answer 4

this is the breaking down of rocks or breaking rocks apart without changing their chemical composition

Question 5

what is chemical weathering

Answer 5

decomposition of rock caused by acidic reactions

Question 6

where does chemical weathering usually happen

Answer 6

in wet and hot conditions

Question 7

is weathering a marine or subaerial process and why

Answer 7

usually are subaerial processes because they usually happen on the cliff face or cliff top

Question 8

what are 4 main types of physical weathering

Answer 8

freeze thaw, salt crystallisation , wetting and drying(slaking) ,biological weathering

Question 9

how does freeze thaw weathering work

Answer 9

when water gets into cracks in rocks and freezes causing it to expand , then when it thaws it contracts , this puts pressure on surrounding rock causing it to crack and break

Question 10

when is freeze thaw most effective

Answer 10

during very cold winters

Question 11

what is salt crystallisation

Answer 11

this is where salt crystals deposit into cracks in rock/cliffs and over time the crystals build up , this puts pressure on surrounding rock causing it to crack

Question 12

what is wetting and drying

Answer 12

this affects rocks made out of clay mostly as when the material expands when it’s wet and contracts when it’s dry , this leads to cracks in the clay rock

Question 13

what does wetting and drying usually lead to

Answer 13

salt crystallisation and freeze thaw

Question 14

what is an example of biological weathering

Answer 14

where the roots of growing plants grow deep into cracks in rocks , causing the cracks to get bigger which means rock segments can break away

Question 15

what are 3 main types of chemical weathering

Answer 15

oxidation , carbonation and hydrolysis

Question 16

what is oxidation weathering

Answer 16

this is where oxygen dissolved in sea water and therefore reacts with it, which causes rocks and cliffs to disintegrate

Question 17

what type of rock does oxidation affect most and what does it cause

Answer 17

iron rich rocks , and causes a yellow/brown rusty colour

Question 18

what is carbonation weathering

Answer 18

this is where CO2 dissolved in rain (acidic rain) creates a weak carbonic acid
the carbonic acid reacts with the calcium carbonate in limestone to form calcium bicarbonate
calcium bicarbonate is very soluble so it’s easily dissolved , this gradually will weather away the rock

Question 19

what is hydrolysis

Answer 19

this is where acidic water reacts with the minerals in rocks/cliffs, which makes weak clays and soluble salts
these are weak materials so make the rock weaker so it’s more likely to break apart

Question 20

what type of rock does hydrolysis affect the most

Answer 20

granite