Depositional processes and landforms

Question 1

Landforms

Answer 1

1. Spit + recurved spit = A beach spit is a long, narrow ridge of sand or shingle that extends from the land into the sea (Example = Holderness coast)

Caused by:
Longshore drift: Longshore drift carries sediment along the coastline in a zig-zag pattern.

Deposition: When the coastline changes direction, the energy of the longshore drift disperses, causing deposition on the sea bed.

2. Sand Dune = A dune is a natural hill or ridge made of sand that forms when wind blows sand into a sheltered area

Formation:
Sand dunes are formed when wind blows sand off the beach and deposits it around an obstacle, like a rock or driftwood. The sand builds up into ridges, called embryo dunes, that grow in size over time

Stabilization
Vegetation, such as marram grass, stabilizes the dunes through a process called plant succession.

Conditions
Sand dunes form where the rate of beach deposition is greater than erosion. The stronger the wind, the higher the dunes will be.

3. Bayhead beach (Lulworth cove)

Swash - aligned feature = where waves break parallel to the shoreline and move sediment into a bay, where a beach forms. Erosion is concentrated at headlands and the bay is an area of deposition

4. Bar
5. Tombolo

Question 2

Why does deposition occur?

Answer 2

Deposition occurs when waves no longer have sufficient energy to continue to transport material

This loss of energy might be due to:
- the wind dropping, removing an energy source
- resistance by obstruction, e.g. a groyne or headland
- dissipation of energy through refraction
- friction from extended transport across shallow angled nearshore and foreshore zone

Sediment is deposited when the force transporting the sediment drops.

• Deposition occurs in two main ways:
• Gravity settling occurs when the energy of transporting water becomes too low to move sediment
• Large sediment will be deposited first, followed by smaller sediment (pebbles -> sand -> silt)

Question 3

4 transportation processes

Answer 3

Saltation = bounce
Solution = can be dissolved
Suspension = Held in suspension
Traction = rolled

Question 4

Berms

Answer 4

Ridges of sand at the high tide mark

Question 5

Cusps

Answer 5

Crescent shaped indentations created by constructive waves

Question 6

Spits ends called

Answer 6

Spits are long, narrow ridges of sand and/or shingle that are attached to the land at one end known as the proximal end. The distal end is in the sea and often extends partly across an estuary. This end can be
hooked and is likely to change its position over time.

Question 7

Recurved spit

Answer 7

Wave refraction

Question 8

Aeolian transport

Answer 8

Wind

Question 9

Vegetation

Answer 9

Important in stabilising sandy coastlines through dune
successional development on sandy coastlines and salt marsh successional development in estuarine areas.