1.1.8: Aeolian, fluvial and biotic processes Flashcards
Aeolian processes
when wind reaches a critical velocity it transports sediment particles which can lead to the development of sand dunes
conditions required for aeolian processes to occur
5
- an abundant supply of sand
- shallow beach gradient
- tidal range that allows large area of sand to dry at high tide
- prevailing offshore winds
- an area inland where windblown sand can accumulate
Which waves needed to form sand dunes
constructive
Ridges
sand dunes
lines of dunes parallel to the coast
Slacks
sand dunes
Hollows found between the dune ridges
Grey dunes
Older dunes where decomposing organic matter creates a humus layer on the surface, making the dunes appear grey
Yellow dunes
Younger dunes with no humus layer
Embryo dunes
Youngest dunes in the earliest stages of formation
Fore dunes
Dunes ridges closest to the sea
Fixed dunes
Older dunes stabilised with vegetation, which are unlikely to change
Blow- out
sand dunes
An 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
Fluvial processes
The erosion, transportation and deposition of sediment by rivers to the coastal zone.
Tidal flats
Muddy areas bordering an estuary
Rills
Shallow channels cut by the action of running water
Salt marshes
Gently sloping, vegetated areas of intertidal mudflats
Biotic processes
examples 2
coral reefs
mangroves
Best conditions for coral growth
4
clear water
sea water temps. between 23-29 degrees C
shallow water less than 100m deep
wave activity
Where are 91% of coral reefs found
Indo-Pacific region
Largest coral reef
The great barrier reef off the Queensland, Australia coast
Mangroves
Form an ecosystem of small trees growing along tropical coastlines where fine sediments have deposited
Largest mangrove forest
The great sundarbans forest in India and Bangladesh covers 1400km squared
