Coasts KQ2

Question 1

What is physical/ mechanical weathering?

Answer 1

Break down of rock, not by chemical alteration, into smaller fragments

Question 2

Name the 4 types of mechanical/ physical weathering?

Answer 2

1. Freeze thaw
2. Pressure release
3. Thermal expansion
4. Salt crystalisation

Question 3

Name the 4 types of mechanical/ physical weathering?

Answer 3

1. Freeze thaw
2. Pressure release
3. Thermal expansion
4. Salt crystallisation

Question 4

What happens in freeze thaw weathering?

Answer 4

water enters joints and cracks, which expand by up to 10% and then release by cooling, repeating cycle breaks these apart

Question 5

What happens in pressure release?

Answer 5

also known as dilation, when underlying rock beneath the surface(which has eroded and weathered) expands and fractures parallel to the surface, these are known as pseudo bedding planes, significant in granite

Question 6

What happens during thermal expansion?

Answer 6

Rock heats and cools, this repeating cycle causes the outer layers to flake off

Question 7

name the 5 types of chemical weathering

Answer 7

Oxidation, Carbonation, solution hydration & hydrolysis
(ollie can’t sell his house)

Question 8

Where is the rate of chemical weathering among the highest?

Answer 8

In the tropics, as Van Hoff’s law states a 10°C can lead a 2.5x increase rate of reaction.

Question 9

Where is the rate of chemical weathering among the lowest, specifically carbonation?

Answer 9

In cooler regions where carbon dioxide is able to dissolve more easily in cooler water

Question 10

Explain the process of hydrolysis, and give an example

Answer 10

Rock minerals react with water e.g. feldspar in granite reacts with hydrogen in water to form kaolin

Question 11

Explain the process of carbonation and give an example

Answer 11

rainwater reacts with CO2 in the atmosphere to form a weak carbonic acids, this reacts with calcium carbonate in rocks to form calcium bicarbonate, which is soluble

Question 12

Describe 2 ways in which biological weathering can take place

Answer 12

1. Tree roots- can exert pressure in joints and when they fall, roots may cause leverage and drag rock to the surface, exposure to further weathering
2. Organic acids- produced due to decomposition, increase acidity of soil and react it with minerals

Question 13

What principal causes mass movement to take place?

Answer 13

When forces acting on material, i.e. gravity exceeds friction of material on a slope

Question 14

Describe how rock fall occurs

Answer 14

On cliffs of 40° + angles, rocks may detach by physical weathering, under the influence of gravity, wave processes may remove this

Question 15

What 2 types of rock slides are there?

Answer 15

These may be linera, with movements along a joint or rotational i.e. slumps

Question 16

Describe how slumps in rock fall occur

Answer 16

slumps usually occur due to undercuts on cliffs, which removes material, by wave erosion. These slumps are also usually made of weak rock, such as clay which get heavier when wet, a layer of sand may also increase pore pressure, as its’ permeable for water to pass through but water can’t pass through clay

Question 17

Describe each of the 5 erosional processes in waves

Answer 17

1. Abrasion- rocks hit against each other until
2. Attrition- rock particles hitting against each other get rounder and smaller over time, eventually forming reach sand
3. Solution- compounds dissolve in water e.g. MgCO3, often the pH may change from 7 to 8, with limited influences, this however is of greater impact in polluted areas but even then the effect is often determined by rock type
4. Hydraulic action- when waves hit cliff face, any water or air is compressed but as waves retreat, this expands, repeated cycle can cause rocks to break apart, average pressure exerted by waves in the Atlantic is up to 11,000kg m^2
5. Pounding, waves bash against rock, this pressure breaks down rock and can reach up to 30000 tonnes/m^2 can be exerted by high energy waves

Question 18

Describe the 4 wave transportation in waves.

Answer 18

1. Solution- its dissolved, and invisible, and usually are released when they evaporate or precipitate out
2. Suspension- smaller sand particles may be held in suspension and carried, often giving water a muddy appearance during storm surges
   3, Saltation- particles too heavy to be carried travel short distances before dropping again
3. Traction- very heavy particles, such as boulders roll along the seabed

Question 19

Give 3 conditions needed for deposition in waves to occur

Answer 19

1. Places when accumulation of sediment exceeds removal
2. At the top of the wave, where for a moment the water is no longer moving
3. when water percolates into the beach

Question 20

What is the settling velocity

Answer 20

Velocity at which sediment particles are deposited

Question 21

Describe the process of erosion in fluvial process

Answer 21

Much of the sediment load is accounted for by mass movement and erosion from river valley sides, and much like wave erosion, most erosion occurs during high energy storm events

Question 22

Describe the process of transportation in terms of the fluvial process

Answer 22

Same processes as waves:
1. Solution- its dissolved, and invisible, and usually are released when they evaporate or precipitate out
2. Suspension- smaller sand particles may be held in suspension and carried, often giving water a muddy appearance during storm surges
3, Saltation- particles too heavy to be carried travel short distances before dropping again
4. Traction- very heavy particles, such as boulders roll along the seabed

Question 23

Describe the process of deposition in terms of the fluvial process

Answer 23

River meets the relatively static body of water, any tides and currents can also provide major resistance and hence loss of energy, leading to major deposition, which is progressive, heavier particles drop first. Flocculation can also occur where particles attract due top electrical charges and become heavier and are hence deposited

Question 24

Describe the process of erosion in terms of the aeolian process

Answer 24

• Fine and dry sand is often easier to carry than wet sand due to cohesion
• ## attrition is also much easier to occur but traction is very limited

Question 25

Describe the process of transportation in terms of the aeolian process

Answer 25

1. Saltation particles are between 0.15 to 0.25mm whilst those that are 0.25-2 mm move by surface creep
2. Same as waves but no solution

Question 26

Describe the process of deposition in terms of the aeolian process, what is the leading cause?

Answer 26

Occurs by drop in energy which may be caused by surface friction with vegetation or any surface irregularities