CP Chapter 7: Aeolian, Fluvial, Biotic Processes, Characteristics and Formation of Landforms

Formation of Sand Dunes

1 - form against obstructions
2 - sand accumulates
3 - dunes grow larger and form rows perpendicular to the wind direction
4 - vegetation can grow (marram grass, sand couch) and help bind the sand and stabilise the dunes
eg. West Wittering, England

Vulnerability

vulnerable to erosion by natural processes and human activity

commonly fenced off and paths are laid to prevent humans from eroding the dunes

Optimum Conditions for Dune Formation

Abundant supply of sand

Low beach gradient

Macro-tidal range

Vegetation

Dune Formation

1 - strong winds

2 - saltation

3 - deposition of sand as wind slows

4 - accumulation of sand to create a foredune

Blowouts

when pioneer plants are eroded from a dune, leaving an empty space in the dune, allows for parabolic dunes to form behind them

Pioneer Plants

stabilise sand dunes, prevent erosion, provide a habitat for insects and small animals

Formation of Salt Marshes

form where spits shelter from wind and waves

require a large input of sediment, tidal mudflats accumulate sediment sediment by deposition, increasing elevation, flooding reduces and allow pioneer plants to grow, creates new ecosystem for organisms to live

Human Factors Affecting Salt Marshes

construction, groynes, fertiliser, arson, overgrazing

Physical Factors Affecting Salt Marshes

storms, destructive wave, lack of sediment

Conditions for Coral Growth

1 - sea temperatures between 21 and 25 degrees

2 - 30-40m from the sea surface

3 - Clear water

4 - salty water, not fresh or full of silt

5 - strong wave action

Mangroves

coastal tropical forests made of saltwater tolerant species

trap sediment and provide nutrients to sea grass and coral reefs

between the tropics, south-east Asia and coastal Africa

coastal protection from wave action