2B.6

Question 1

What is a sub-aerial process?

Answer 1

Process that occur on the cliff face rather than the cliff foot.

Question 2

Are mass movements and weathering sub aerial processes?

Answer 2

Ye at coasts

Question 3

What is weathering?

Answer 3

The breakdown of rocks in situ by mechanical, chemical or biological agents.

Question 4

How is weathering different from erosion?

Answer 4

Because erosion is rather the breakdown and removal of rock by an external agent (winds/waves/rivers/ice)

Question 5

What are mass movements?

Answer 5

The movement of rocks/sediment downslope due to gravity.

Question 6

How are weathering and mass movements linked?

Answer 6

Weathering often triggers many mass movements.

Question 7

What influences how vulnerable a cliff is to mass movements?

Answer 7

Lithology and structure of a cliff
Weathering processes = loosening of cliff faces
Water = saturate soil or not?
Angle of slope

Question 8

What are the types of weathering?

Answer 8

Mechanical (physical)
Biological
Chemical

Question 9

What are types of mechanical weathering?

Answer 9

Freeze thaw
Salt crystallisation
Wetting and drying

Question 10

What are the types of chemical processes?

Answer 10

Carbonation

Oxidation

Question 11

What are the types of biological weathering?

Answer 11

Plants roots
Rock boring
Seaweed acids

Question 12

What is freeze-thaw weathering?

Answer 12

Water into cracks freezes expands (9%) causing pressure into rocks cracking them apart. Most vulnerable are well jointed rocks.
Happens in fluctuating temperature areas. And is repeated. Can cause large rock falls on jagged cliff faces.

Question 13

What is salt crystallisation weathering?

Answer 13

Water spray hits cliffs which gets into cracks evaporates leaving salt which expands exerting pressure breaking apart well jointed rocks ie Limestone happening in hotter climates. This creates scree at cliff foots.

Question 14

What is wetting and drying weathering?

Answer 14

Rocks rich in clay expand when wet and contract when dry which repeats causing them to spit. This makes the cliff vulnerable to slumping.

Question 15

What is carbonation weathering?

Answer 15

Rocks ie limestone being slowly dissolved as it reacts with weak carbonic acid in rainwater. This widens gaps on flat surfaces ie wave-cut platforms making them vulnerable to other processes

Question 16

What is oxidation?

Answer 16

When oxygen mixes with iron in a rock causing it to rust making rocks weaker ie sandstones and shows are vulnerable. This causes crumbling because of weak intermolecular links.

Question 17

What is plant root weathering?

Answer 17

Roots growing into cracks slowly widening areas which can be effective on vegetated faces. Ie trees being removed = destabilised. This leads to rock falls

Question 18

What is rock boring weathering?

Answer 18

Small scale organisms dig into rocks secreting acids that dissolve rocks. Sedimentary rocks are vulnerable as they are weaker. Holes make it vulnerable to further weathering

Question 19

What is seaweed acids weathering?

Answer 19

When plants ie kelp contain acids ie sulphuric acids which can burst into rocks dissolving them. This can lead to crumbling..

Question 20

What are the types of mass movements events?

Answer 20

Rock falls or talus slopes.
Rotational slumping 
Flow
Block falls
Soil creep

Question 21

What are rock falls mass movements?

Answer 21

When freeze-thaw weathering gets int steep slopes (75°) only a rock

Question 22

What is rotational slumping mass movements?

Answer 22

Unconsolidated rock is impermeable and malleable allowing slip lanes which are curved by having low pore pressure.

Question 23

What is flow mass movements?

Answer 23

Saturated soil is exceeded infiltrated soil leading to release of water causing leakages.
Clay becomes softer (wetting and drying)

Question 24

What are block falls mass movements?

Answer 24

In jointed rocks planes are parallel to slopes.
More water reduces friction which increases sliding
In some events rocks can slide over underlying rocks

Question 25

What is soil creep mass movements?

Answer 25

When there is a slow continual process that soil individual particles move downhill due to gravity