Aeolian, Fluvisn And Biotic Processes And Rhe Associated Landforms In Coastal Environments

Question 1

Define aeolian

Answer 1

Relates to wind activity and how the wind eroded, transports and deposits sediment

Question 2

Conditions required to form a sand dune

Answer 2

Abundance of sand
Shallow beach gradient 
Large tidal range so sand can dry out
Prevailing onshore winds
An area inland for sand to accumulate

Question 3

Formation of sand dunes

Answer 3

Constructive waves deposit sediment on the beach.
Winds blowing onshore move sand inland by creep(rolling) or saltation.
Where an obstacle or vegetation reduces wind velocity, the sand is deposited and quickly accumulates.
Plants such as sea couch grass and marram grass become established, increasing sand accumulation and forming an embryo dune.
Continued deposition leads to the embryo dune forming a ridge.
New embryo dunes form in front of the ridge, repeating the process.
Gradually older dunes become covered in vegetation and are stabilised.

Question 4

Define ridges

Answer 4

Lines of dunes parallel to the coast

Question 5

Define slacks

Answer 5

Hollows found between the dune ridges

Question 6

Define Grey dunes

Answer 6

Older dunes where decomposing organic matter creates a humus layer on the surface, making them appear grey

Question 7

Define yellow dunes

Answer 7

Younger dunes with no humus layer

Question 8

Define embryo dunes

Answer 8

Youngest dunes in the early stages of formation

Question 9

Define fore dunes

Answer 9

Dune ridges closest to the sea

Question 10

Define fixed dunes

Answer 10

Older dunes stabilised with vegetation, which are unlikely to change

Question 11

Define blow out

Answer 11

Area of dune that has been eroded by the wind often due to its protective cover of vegetation being removed by animal or human activity

Question 12

What is a tidal flat and how is it formed?

Answer 12

Level muddy areas bordering an estuary.

Edges of estuaries are sheltered and so are low energy coastlines. Deposition of fine sediment is the main process.
At low tide the mudflat is uncovered. Fresh water from tributaries flows across mudflat in small channels called rills.
Eg morecambe bay on Lancashire coast

Question 13

What are salt marshes and how are they formed?

Answer 13

Gently sloping vegetated areas of intertidal mudflats.
Found in low energy sheltered locations such as estuaries, lagoons.
Lack of marine erosion allows salt tolerant pioneer plant communities to colonise. Salt marshes are dissected by channels and rills.

Question 14

What is fluvial processes?

Answer 14

Provide a significant supply of sediment to the coastal zone. Low energy coastal environments where deposition is dominant process.

Question 15

What are coral reefs how are the formed?

Answer 15

Calcium carbonate structures secreted by tiny animals called polyps.
Clear water for light penetration, temperature 23-29*, shallow less than 100m, wave activity to aerate.
Changes in condition can kill coral

Question 16

Mangrove formation and about

Answer 16

Mangroves form an ecosystem of small trees growing along tropical coastlines where fine sediments have been deposited.
Vegetation is salt tolerant and able to survive in waterlogged mud with extreme temp.
Upwards roots absorb air.
They reduce wave energy and protect coastlines. Can reduce tsunamis.