Landforms of deposition

Question 1

What are some landforms of deposition

Answer 1

Beaches
Spits, bars, tombolos
Sand dune
Salt marsh

Question 2

What is a beach

Answer 2

accumulation of material deposited by waves

Question 3

What factors define a beach

Answer 3

sediment size
wave type
wave angle

Question 4

What are the 4 types of beaches

Answer 4

Shingle or Sand
Drift or swash

Question 5

Describe shingle and sand beaches

Answer 5

Shingle has a high percolation rate, so there is lots of swash but no backwash, making them steep and narrow

Sand has a low percolation rate, so there is lots of swash and backwash so is more flat and wide

Question 6

Describe drift and swash beaches

Answer 6

Drift beaches are parallel to the shoreline and have lots of sediment transported along them (regular coast)

Swash beaches are parallel to the wave crests and do not have lots of sediment transportation (irregular coastline)

Question 7

What are some features of a beach

Answer 7

Berms - (ridges of sand and pebble found at high tide marks, by deposition)

Runnels - (grooves in sand parallel to shore, by backwash)

Cusps

Question 8

What are cusps and how are they made

Answer 8

Crescent shaped indentations

Form on mixed beaches with a large tidal range, and waves parallel to beach

Sides channel swash into the centre, strong backwash moves through centre, deepens cusp and makes rip current

Question 9

What is a spit

Answer 9

Long narrow piece of land with one end to the main land and the other jutting out to sea

Question 10

How are spits formed

Answer 10

1.Sand deposited in sheltered water (longshore drift)

2. Feature projects, storm build up more material for greater permanence
3. Eventually is stopped by deep water
4. Distal end curves toward land due to wave refraction and second most dominant wind

Question 11

What is a bar and how do they form

Answer 11

A bar is when a spit connects to 2 headlands , creating a lagoon behind it

Question 12

What is a tombolo and how do they form

Answer 12

A tombolo is when a beach extends outwards to join an offshore island

Question 13

What is a barrier island and how do they form

Answer 13

Elongated bank of deposited sand/shingle parallel to the coastline but not submerged by high tide. If sand dunes develop, it becomes a barrier island rather than a barrier beach. Often the sheltered area becomes a lagoon or coastal marsh

Although they make up 13% of the worlds coastline, their origin is unknown, although some say they are submerged beach ridges

Question 14

What is a sand dune

Answer 14

Accumulation of sand shaped into a mound by the wind

Question 15

What conditions do sand dunes need to form

Answer 15

Constructive waves
Abundant sand on a gentle profile
Prevailing onshore winds
High tidal range
VEGETATION

Question 16

Why are plants so important for sand dunes

Answer 16

Make more sand accumulate
Roots fix sand into place
Reduces wind speed close to surface

Question 17

Give an example of a key plant for sand dunes and some qualities of it

Answer 17

marram grass
1. Spreads rapidly
2. Long roots to touch water table
3. Silver leaves reflect heat
4. Leaves fold to retain moisture

Question 18

What are the 4 stages of dune development

Answer 18

Embryo (hummocky)
Fore/Yellow
Grey

Question 19

How do embryo dunes form

Answer 19

Sand trapped by obstacles like driftwood. They grow upwards through accumulating sand and stabilise the surface. The growth of plants leads to hummocky dunes, where the addition of organic matter (marram grass) creates water retention

Question 20

What happens at fore, yellow and grey dunes

Answer 20

Upward growth of embryo dunes keeps them out of reach of storm tides, meaning they can grow tall. At first they appear yellow due to lack of organic matter, but as plants grow they become more grey, and more fixed

Question 21

What happens at dune heaths

Answer 21

Ridges start to stick out, of the grey and yellow dunes which cuts off the sand supply, so the features become smaller

Question 22

What are some features of sand dunes

Answer 22

Dune slack - depressions in the sand dune near the water table leading to damp conditions

Blowout - Bare area of dune caused by erosion

Question 23

What are mudflats

Answer 23

A coastal wetland

Question 24

What conditions are required for a mudflat to form

Answer 24

Sheltered shoreline
Mix of fresh and salt water (estuary)
Lots of material (silt and clay)
Low lying, submerged at high tide

Question 25

How are mudflats developed

Answer 25

1. Sea water an river water meet, bringing together fine sediments
2. The 2 flows settle out suspension through flocculation (particles aggregate together to form larger particles) and they sink to the sea bed
3. Over time the sediment builds, and at low tide the mud is exposed

Question 26

What are salt marshes

Answer 26

Coastal grassland

Question 27

What conditions are required for a salt marsh to form

Answer 27

The same as mudflats but with VEGETATION

Question 28

Give an example of key halophyte for a salt marsh to form (not algae)

Answer 28

Spartina grass
Has a 2 root system

1. One root is fine and binds mud
2. One root is thick and deep to anchor it
3. Tall so they don’t drown

Question 29

Give another example of a key halophyte for a salt marsh to form

Answer 29

Algae has…
1. High salinity
2. High turbidity
3. Long inundated periods
4. Low oxygen levels

Allowing it to slow currents and deposit material

Question 30

How (in long) do salt marshes develop

Answer 30

1.Mudflats develop and algae grows on them , building material

2. Low marsh areas become colonised by pioneer plants like Spartina,
3. High marsh areas are completely covered by pioneer plants, creating a dense 15cm thick mat of vegetation and allows soil to develop
4. More and more mud builds and it grows below the water level

Question 31

What are the 2 types of spits

Answer 31

Simple

Compound - mini spits and recurved ridges within