coastal systems -geomorphological processes (sub aerial -weathering)

Question 1

what are sub aerial processes?

Answer 1

.processes that occur on land

Question 2

what is meant by weathering?

Answer 2

.the breakdown of material in situ

Question 3

where does weathering occur?

Answer 3

.wherever rock is exposed to the weather or atmosphere

Question 4

where does the mercy of weathering processes originate from?

Answer 4

.the sun, in the form of rain or radiation

Question 5

what are the 3 types of weathering?

Answer 5

.mechanical
.chemical
.biological

Question 6

what are the 2 types of mechanical weathering?

Answer 6

.freeze thaw
.wetting and drying

Question 7

what is meant by mechanical weathering?

Answer 7

.break up of rocks with no chemical change

Question 8

what is freeze thaw weathering?

Answer 8

.when water enters a crack in the rock when it rains
.in cold weather, the water freezes and this causes its volume to increase by 10% -causes cracks to widen
.this repeats over time and eventually fragments of rock break off and collect at the base of the cliff as ‘scree’

Question 9

what is wetting and drying?

Answer 9

.where rocks that are rich in clay eg -shale expand when they get wet -due to rainfall
.when they dry, they contract
.this repeats over time which causes them to crack and break apart

Question 10

what are the 2 types of biological weathering?

Answer 10

.roots
.birds/animals

Question 11

what is meant by biological weathering?

Answer 11

.breakdown of rocks by organic (living) activity

Question 12

how do roots cause biological weathering?

Answer 12

.plants grow on cliffs and the plant’s roots grow into small cracks on the cliff face
.as the roots grow, they force the cracks to widen so the rock breaks apart

Question 13

how do birds and animals cause biological weathering?

Answer 13

.birds and animals dig burrows into the cliff -causing rock to break apart
.marine animals can also burrow into rocks eg piddock fish

Question 14

what is chemical weathering?

Answer 14

.breakdown of rocks by changing the chemical composition – involves the dissolving of rocks due to chemical reaction

Question 15

what are the 3 types of chemical weathering?

Answer 15

.carbonation
.oxidation
.solution

Question 16

how does carbonation cause chemical weathering?

Answer 16

.rainwater absorbs CO2 from the atmosphere, making it slightly acidic carbonic acid -the carbonic acid reacts with calcium carbonate in rocks eg -chalk or limestone to form calcium bicarbonate
.rocks dissolves over time

Question 17

how does oxidation cause the chemical weathering of rocks?

Answer 17

.oxygen reacts with iron in rocks -this forms iron oxide
.iron oxide is weak and therefore more vulnerable to breaking down

Question 18

how does solution result in the chemical weathering of rocks?

Answer 18

.same process as carbonation