25 terms

Coastal Processes

Marine processes
Operate upon a coastline and are connected with the sea such as waves tides and longshore drift.
Sub-aerial processes
Includes processes that slowly break down the coastline weaken the underlying rocks and allow sudden movements or erosion to happen more easily. Material is broken down insitu remaining in or near its original position. These may affect the shape of the coastline and include weathering mass movement and run off.
Hydraulic action
impact on rocks of the sheer force of the water itself.
Wave quarrying
breaking wave traps air as it hits a cliff face. Force of the water compresses this air into any gap in the rock face creating pressure in joint or fissure. As water pulls back there is an explosive effect of the air under pressure being released.
Material the sea has picked up also wears away rock faces.
Rocks in the sea which carry out abrasion are slowly worn down into smaller and more rounded pieces.
Dissolving of calcium based rocks.
Wave steepness and breaking point
steeper waves and high energy waves have greater erosive power than low energy waves.
How far the wave has travelled determines how much energy has been generated in it.
Sea depth
a steeply shelving seabed at the coast will create higher and steeper waves.
Coastal configuration
Headlands attract wave energy through refraction.
Human activity
People may remove protective materials from beaches which leads to more erosion or may reduce erosion with sea defences.
characteristics of rocks.
Differential erosion
Variation in the rates at which rocks wear away.
Concordant coastline
Rocks running parallel to the coastline.
Discordant coastline
Rocks run at right angles to the coast.
The angle at which the rocks dip can determine how steep a cliff is.
Large stones and boulders are rolled and slid along the seabed and beach by moving seawater which happens in high energy environments.
Small stones bounce along the seabed and beach which is associated with relatively high energy conditions.
Very small particles of sand and silt are carried along by the moving water.
Dissolved materials are transported within the mass of moving water.
Aeolian processes
The entrainment, transport and deposition of sediment by wind.
Surface creep
A process similar to traction where wind rolls or slides sand grains along the surface.
Where the wind is strong enough to temporarily lift the grains into the airflow to heights of up to one metre for distances up to 20 to 30m.
Sub-aerial processe
slowly breakdown the coastline.