weathering

Question 1

what is weathering?

Answer 1

the break down of rocks over time

Question 2

explain the process of positive feedback in weathering

Answer 2

rate of rock removal is greater than the rate of weathering. promoting further weathering. increasing amount of erosion that occurs .

Question 3

explain the process of negative feedback in weathering

Answer 3

removal of rock rate is slower than rate of weathering. leading to a build up of debris at the base. reducing the exposed cliff areas and rate of weathering and erosion

Question 4

what are the three types of weathering?

Answer 4

mechanical (freeze-thaw, salt crystallisation, wetting and drying)

chemical (carbonation, oxidation, solution)

biological (plant roots, birds, seaweed acid, decaying vegetation)

Question 5

what are the three types of mechanical weathering?

Answer 5

freeze-thaw

salt crystallisation

wetting and drying

Question 6

what are the three types of chemical weathering?

Answer 6

carbonation

oxidation

solution

Question 7

what are the four types of biological weathering?

Answer 7

plant roots

birds

seaweed acids

decaying vegetation

Question 8

explain what is free-thaw weathering?

Answer 8

water enters cracks
freezes
water expands by around 10% in volume
increasing pressure on rock
cracks develop
cracks grow and cliff grows weak
more vulnerable to other processes of erosion

Question 9

explain what is salt crystallisation weathering?

Answer 9

seawater evaporates
salt left behind
crystals grow over time
exert pressure on rock
forcing cracks to widen

Question 10

explain what is wetting and drying weathering?

Answer 10

clay expands when wet
contract when dry
continues over time
causes rocks and cliffs to breakup

Question 11

explain what is carbonation weathering?

Answer 11

rainwater absorbs CO2 from the air
weak carbonic acid
reacts with calcium carbonate in rocks
form calcium bicarbonate

Question 12

explain what is oxidation weathering?

Answer 12

minerals are exposed to air because of cracks
mineral becomes oxidised
increases its volume
causing rock to crumble

Question 13

explain what is solution weathering?

Answer 13

when rock minerals are dissolved

Question 14

explain what is plant root weathering?

Answer 14

roots of plants grow into cracks
exert pressure
splitting rock

Question 15

explain what is bird weathering?

Answer 15

eg puffins dig burrows into cliffs
weakening them
making erosion more likely

Question 16

explain what is seaweed acid weathering?

Answer 16

some seaweed contain sulphuric acid
if this hits rocks or cliffs
acid will dissolve some of the rocks minerals

Question 17

explain what is decaying vegetation weathering?

Answer 17

water that flows through decaying vegetation
and then over coastal areas
will be acidic
thus causing chemical weathering

Question 18

what can effect the prominence of weathering?

Answer 18

the temperature and climate

colder — mechanical more common
warmer — chemical more common