Coastal Formations

Question 1

Discordant coastline

Answer 1

Coastline and geology are at right angle to each other

Question 2

Concordant coastline

Answer 2

Coastline and geology are parallel to each other

Question 3

Wave refraction

Answer 3

Waves undergo a change in direction as it approaches headlands and bays

Question 4

El nino

Answer 4

A reverse in an ocean current in the South Pacific Ocean

Question 5

Headland and bay formation

Answer 5

-require a discordant coastline where geology consists of alternating bands of hard and soft rock which face at right angle to the sea
-destructive wave erode coastline via erosional processes
-harder rock erodes slower and sticks out from the fast eroding soft rock
-this is a headland
-the bay is formed when soft rock is eroded backwards
-wave refraction then takes place and creates a beach in the bay

Question 6

How does wave refraction create a beach within a bay

Answer 6

Wave energy is concentrated onto the headland, meaning the bay receives low energy waves (constructive) which pushes sediment up due to its larger swash than backwash

Question 7

Stack formation

Answer 7

-weathering processes such as salt crysallisation weaken rock face
-headland is attacked by destructive waves which have been refracted onto it
-waves attack the base of headland by series of erosional processes
-waves strip away material by throwing rocks at the headland (abrasion)
-processes create a geo in the headland
-overtime the geo becomes a cave
-continued erosion eats away material and forms an arch
-arch is weak and collapses from gravitational forces
-leaves a vertical column of rock called a stack

Question 8

What is a geo

Answer 8

A small hole in the rock face from erosional processes such as abrasion of hydraulic action

Question 9

What are the inputs of energy for a stack

Answer 9

-Gravitational energy (causes arch to collapse)
-Destructive waves (erode the headland)
-Wind energy (creates high energy waves)
-tidal energy

Question 10

What are the inputs of matter for a stack

Answer 10

Rocks in water used in abrasion

Question 11

What processes occur in the formation of a stack

Answer 11

Weathering
Erosion
Mass movement
Wave refraction

Question 12

What are the components of a stack

Answer 12

Geo
Cave
Arch
Headland
Stack

Question 13

What sources of beach material are there

Answer 13

-river (90%)
-offshore (5%)
-cliff erosion (5%)

Question 14

What is a beach

Answer 14

An accumulation of material deposited between positions of high and low tide

Question 15

Inputs vs outputs

Answer 15

The inputs of material must be greater than outputs for a beach to form

Question 16

What gradient do sand beaches have

Answer 16

Gentle (5°)

Question 17

What gradient do shingle beaches have

Answer 17

Steeple (10-20°)

Question 18

What waves are needed to produce shingle beaches

Answer 18

High energy, as the material is larger

Question 19

What type of beach profile do destructive waves form

Answer 19

Shallow flat beaches, the backwash is stronger than swash so material is eroded from the beach

Question 20

What beach profile do constructive waves form

Answer 20

Steep beaches, as swash is higher than backwash so material gets deposited onto the beach

Question 21

How is a sandy beach formed

Answer 21

Usually formed in sheltered bays where low energy constructive waves transport material onto the shore, the swash is higher than the backwash so so material is moved up the beach.

Question 22

What is a berm

Answer 22

A small ridge that develops at the position of high tide resulting from deposition at the top of the swash