weathering

Question 1

weathering definition

Answer 1

the breakdown of rock to form transportable material

Question 2

5 factors controlling weathering

Answer 2

1. rock properties
2. climate
3. presence of soil
4. length of exposure time
5. topography

Question 3

moving from the north to the south pole, what are the 7 climates

Answer 3

polar
temperate
subtropical
tropical
subtropical
temperate
polar

Question 4

3 types of weathering

Answer 4

chemical and mechanical
and biological (combo)

Question 5

dominant process of weathering in cold and arid climates

Answer 5

mechanical weathering

Question 6

agents of mechanical weathering

Answer 6

• pressure release
• water (freeze-thaw, wetting-drying, crystallise salt)
• heat

Question 7

how does mechanical weathering increase the weathering process as a whole?

Answer 7

increases total surface area exposed to further weathering - cascades

Question 8

explain pressure release weathering

Answer 8

rocks form at high pressures underground . When they rise to the surface the pressure on them decreases and the rock mass expands. joints form.

Question 9

true or false. All rock masses at or near the surface contain joints?

Answer 9

true (virtually all)

Question 10

exfoliation (sheet joining)

Answer 10

rock breaks apart in layers parallel to surface, as it is uncovered and expands

Question 11

frost wedging

Answer 11

expansion of ice in joints in cold and alpine environments

Question 12

wetting and drying (common on the coast)

Answer 12

clays absorb water and expand, dry and shrink. continuously.

Question 13

salt crystallization (aka haloclasty) what? where?

Answer 13

saline solutions seep into joints and the water evaporates, leaving salt crystals.. These expand when heated and pressure exerted on rock. common in arid climates and coasts

Question 14

thermal expansion

Answer 14

extreme ranges in temperature shatter rocks in DESERT environments. Different expansion rates of rock minerals causes shattering

Question 15

what is one thing essential in chemical weathering

Answer 15

water, therefore prevelant to wet regions

Question 16

4 types of chemical weathering

Answer 16

1. dissolution
2. hydrolysis
3. oxidation
4. hydration

Question 17

dissolution

Answer 17

complete removal of mineral from rock. eg acid rain

Question 18

hydrolysis

Answer 18

water changes composition and size of minerals in a rock. Which are less resistant to weathering. rock is then physically broken down

Question 19

in what rock is hydrolysis common

Answer 19

granite

Question 20

red soils produced from

Answer 20

oxidation weathering

Question 21

hydration

Answer 21

water added to crystal structure which creates a new mineral of greater volume.

Question 22

according to Bowen’s reaction series, the first to crystallise will be the ______ to weather on the goldich series

Answer 22

first

Question 23

roots splitting rocks apart and producing acids, are an example of?

Answer 23

biological weathering

Question 24

chemical weathering most effective in polar regions, TRUE/FALSE?

Answer 24

FALSE. least effective here, needs warmth and moisture

Question 25

4 effects of weathering

Answer 25

1. strength decrease
2. loss of elasticity
3. density increase
4. increased porosity

Question 26

erosion

Answer 26

detachment and transportation of weathered surface particles

Question 27

soil erosion snowball effect

Answer 27

removes topsoil which provided the nutrients and water for plant growth. less vegetation leads to more erosion and so on…

Question 28

severe soil erosion forms…

Answer 28

gullies

Question 29

where is soil erosion most active?

Answer 29

where it is difficult for rain to infiltrate into the ground

Question 30

describe ‘piping’?

Answer 30

subsurface soil erosion. invisible and therefore very dangerous . eg sinkholes

Question 31

in arid areas, what causes soil erosion?

Answer 31

wind. can also form deserts in semi-arid places