Coastal processes

Question 1

weathering

Answer 1

this is the breakdown of the rock situ (ie the stone doesn’t move)

Question 2

what are the different types of weathering?

Answer 2

-chemical
-mechanical

Question 3

chemical weathering

Answer 3

caused by a chemical reaction when rainwater hits rock and decomposes it

Question 4

what are the different types of chemical weathering?

Answer 4

-carbonation
-hydrolysis
-oxidation

Question 5

carbonation

Answer 5

when carbonic acid in rain water reacts with calcium carbonate in limestone to form calcium bicarbonate, this is soluble, so limestone is carried away in solution

Question 6

hydrolysis

Answer 6

when acidic rainwater breaks down the rock, causing it to rot

Question 7

oxidation

Answer 7

when rocks are broken down by oxygen and water

Question 8

mechanical weathering

Answer 8

results in rocks being disintegrated rather than decomposed, it is usually associated with extremes of temperature

Question 9

what are the different types of mechanical weathering?

Answer 9

-freeze thaw weathering
-salt wathering

Question 10

freeze thaw weathering

Answer 10

Happens when water enters cracks in rock. When the night temp falls below freezing, this water freezes and increases in volume by nine percent, putting pressure on the rock around the crack. If daytime temp rises above freezing, the ice will thaw and relieve the pressure. Constant repetition of this daily freezing and thawing cycle causes angular rock fragments to break away and collect at scree at the base of the cliff.

Question 11

salt weathering

Answer 11

when salt spray from the sea gets into a crack in a rock, it may evaporate and crystalise, putting pressure on the surrounding rock and weathering the structure

Question 12

mass movement

Answer 12

is a result of different coastal processes

Question 13

what are the different types of mass movement?

Answer 13

-sliding
-slumping
-rock falls

Question 14

sliding

Answer 14

large clumps of rock slide down the slope quickly without warning

Question 15

slumping

Answer 15

the clay becomes saturated during heavy rainfall and oozes down towards the sea as part of a mud or debris flow

Question 16

where is slumping most common?

Answer 16

where cliffs are made of clay

Question 17

rock falls

Answer 17

well joined rock faces are prone to freeze thaw weathering, which results in falling rocks losing contact with the rock face, at the bottom of the cliff they can fan out to form scree slopes

Question 18

what are the different processes of erosion?

Answer 18

-hydraulic action
-abrasion
-attrition
-solution

Question 19

hydraulic action

Answer 19

water crashes against cliffs and the air and water is compressed into the cracks, when the sea moves away again the air expands, explosively weakening the rocks, enlarging the cracks and breaking pieces off

Question 20

abrasion

Answer 20

very effective as it’s caused by broken rock fragments battering the land and breaking off other pieces of rock

Question 21

attrition

Answer 21

occurs when rock fragments collide and get worn down into smoother and smaller pebble

Question 22

solution

Answer 22

involves chemical action of sea on rock, if the rock is limestone, it dissolves in the sea water, some sea salts can also react with certain rocks and cause them to disintegrate

Question 23

what is longshore drift?

Answer 23

-longshore drift happens when waves break down at an oblique angle to the shore due to prevailing winds
-this means that each wave pushes material along the beach a bit more
-many depositional features such as spits are formed by this process

Question 24

what is transport along the coast?

Answer 24

when waves move material across a beach

Question 25

what are the different types of transportation?

Answer 25

-suspension
-solution
-traction
-saltation
-deposition

Question 26

suspension

Answer 26

fine sediment is carried as a suspension in the water, making it look muddy or murky

Question 27

solution

Answer 27

dissolved material is carried along in solution so you can’t see it

Question 28

traction

Answer 28

larger pebbles are rolled along the sea bed

Question 29

saltation

Answer 29

small pebbles are moved when one pebble hits another, causing it it bounce, this bouncing can set up a chain reaction

Question 30

deposition

Answer 30

this is the dumping of eroded material on the land by constructive waves, it happens when waves have less energy, it creates a variety of landforms