Landforms and landscapes of coastal deposition

Question 1

How much of the worlds coastlines are depositional?

Answer 1

20%

Question 2

How much of the worlds coastline is suffering from net erosion?

Answer 2

70%

Question 3

On average what is the gradient of beaches?

Answer 3

Less than 5 degrees

Question 4

Why does beaches have a small gradient?

Answer 4

because the sand becomes compacted and doesn’t allow much percolation which strengthens the backwash.

Question 5

Complete the sentence:
The ………… the material, the ……….. the beach because more percolation occurs and the …………… is weaker.

Answer 5

larger, steeper, backwash

Question 6

Give an example of a spit.

Answer 6

Hurst castle spit (Hampshire)

Question 7

Give an example of a bar.

Answer 7

Slapton Ley ( Devon)

Question 8

What is a tombolo?

Answer 8

If a spit joins up to an island it creates a tombolo.

Question 9

Give an example of a tombolo?

Answer 9

Chesil Beach

Question 10

What are offshore bars and how do they form?

Answer 10

When mounds of sand and gravel are deposited beyond a shoreline
- some formed as a result of long currents that develop a trough and bar feature in the nearshore zone
- others form when there are storms as the destructive waves with a strong backwash drag the sediment offshore.

Question 11

What are beach inputs?

Answer 11

. beach nourishment
. cliff and dune erosion
. fluvial sediment
. longshore drift
. swash

Question 12

What are beach outputs?

Answer 12

. backwash
. sand mining
. longshore drift
. storm events

Question 13

What are ridges and runnels?

Answer 13

a series of ridges and troughs running parallel to the coast near the low water mark

Question 14

How are ridges and runnels formed?

Answer 14

ridges are formed by the deposition during backwash and runnels are formed from when the water runs back to the ocean

Question 15

What are ripples?

Answer 15

relatively small, elongated ridges that form on the beach

Question 16

How are ripples formed?

Answer 16

when waves and currents flow across loose sand which is dragged along the bottom and is piled up

Question 17

What are cusps?

Answer 17

semicircular shaped depressions

Question 18

How are cusps formed?

Answer 18

formed by the waves reaching the same point and backwash drags the finer material down the centre

Question 19

What are berms?

Answer 19

a series of small ridges that form near the high tide mark

Question 20

How are berms formed?

Answer 20

Deposited by the swash of constructive waves

Question 21

What is a storm beach?

Answer 21

a ridge found near the back of the beach composed of larger sediment

Question 22

How is a storm beach formed?

Answer 22

Deposited by waves during storm events.

Question 23

What is Aeolian processes?

Answer 23

Wind processes

Question 24

Where do sand dunes develop?

Answer 24

. largely sandy beaches
. large tidal zone exposing a large beach
. shallow beach gradient- provide good conditions for sediment transport
. persistent onshore winds- to dry out and move the sand particles by saltation inland.

Question 25

What are sand dunes?

Answer 25

small ridges or hills of sand found at the top of a beach, above the usual maximum reach of the waves.

Question 26

What is Psammosere?

Answer 26

An ecological succession that began life on newly exposed coastal sand. Most common psammoseres are sand dunes.

Question 27

What is a climax vegetation?

Answer 27

The dominant mix of vegetation species that characterize an environment given time for colonization to occur and reach stability.

Question 28

What is plant succession?

Answer 28

A directional change in the types of plant species that occupy a given area through time. It involves the process of colonization, establishment and extinction.

Question 29

How does wind transport sediment along the beach?

Answer 29

Wind carries sand by saltation: grains bounce along. If the wind is very strong it can carry it in the air. It can also creep along

Question 30

How do sand dunes form?

Answer 30

. drought and salt tolerant plants begin to colonize the sand
. embryo dunes develop where plants and obstacles catch the sand.
. foredunes develop as when the plants grow more sand is accumulated.
. The increase in nutrients cause more plants to grow.
. Then grey dunes form when they are covered in 100% vegetation.
.

Question 31

What are salt marshes?

Answer 31

• Halosere environments (tolerate salty conditions)
• Consists of silt and mud
• protect shorelines from erosion by buffering wave action and trapping sediment

Question 32

Name a salt marsh.

Answer 32

Keyhaven Marshes (behind Hurst castle spit)

Question 33

What are the conditions for a salt marsh to form?

Answer 33

• sheltered river estuaries, behind spits
• when wave energy is low and sediment is available
• when the process of flocculation occurs

Question 34

What is flocculation?

Answer 34

When salt and fresh water mix causing clay particles to stick together which make them heavier which then leads to deposition

Question 35

How do salt marshes form?

Answer 35

1. mud and other materials begin to accumulate in a sheltered area along the coast
2. Spartina begin to develop and catch more mud
3. mud gets thicker then more species of plants develop
4. Mud rises above sea level so other plants like reeds grow due to no salt water
5. these larger plants then slow the currents
6. trapped sea water will evaporate leaving salt pans where plants can develop
7. then tolerant trees like ash and oak start to grow

Question 36

What factors affect salt marsh development?

Answer 36

. sea level
. weather
. human action
. climate
. wave type
. sediment supply

Question 37

Name human threats to salt marshes.

Answer 37

. coastal management strategies
. oil pollution
. dredging
. agriculture
. development

Question 38

Name natural threats to salt marshes.

Answer 38

. climate change- rising sea level
. storms
. changing temperatures and rainfall patterns