Covering topics such as population dynamics, rocks and weathering processes, plate tectonics, slope systems, case studies, and plate boundaries, this guide offers concise yet thorough explanations supplemented with illustrative diagrams and examples. Additionally, it includes a selection of past pa...
Littoral Zone
The coast as a system
● As with any geographical system, the coast, as a system, has inputs, stores,
transfers and outputs
● The system constantly strives to be in a state of dynamic equilibrium
● The coast can be viewed as both an open system and a closed system
○ It is an open system because it receives inputs from the lithosphere,
atmosphere, hydrosphere, biosphere and cryosphere
○ However, during research and coastline management the coast can be
seen as a closed system where a specific sediment cells examined
The coast as a system
● There are examples of positive feedback at the coast
○ As waves erode the cliff, material is released
○ This material abrades the cliff which results in even more cliff erosion
● There are also examples of negative feedback at the coast
○ As the shore is eroded, material makes the wave cut platform wider
, ○ This can absorb wave energy and reduce the impact at the base of the
cliff
The littoral zone
● The littoral zone is the area of the coast that can be affected by wave action
● It is a dynamic zone which means that it is constantly changing due to the
interaction between processes on land and in the sea
● These changes can be:
○ Long term due to climate or sea level change
○ Short term due to the tides, waves and storms
● It is divided into four zones:
○ Backshore is usually beyond the influence of wave action but can be
affected during storm events
○ Foreshore is the intertidal area between high and low tide
○ Nearshore is the breaker zone where friction between the seabed and
the waves causes them to break
○ Offshore is the area outside t
he influence of waves
The littoral zone
Long Term Processes
● Coastal systems are affected by long term factors which include geology and
changes in sea level
Geology
● The geology is the characteristics of the land which includes both:
○ Rock type
○ Rock structure
● Coasts can be classified as:
○ Rocky
, ○ Sandy
○ Estuarine
● They can also be classified as:
○ Concordant - where different rock types run parallel to the coast
○ Discordant - where different rock types run at right angles to the coast
Sea level change
● Sea level change can occur as a result of:
○ Global warming - natural and enhanced
○ Tectonic activity - which can lead sections of land to rise or subside
● Longer term sea level change can be:
○ Eustatic - when the sea level itself changes
○ Isostatic - when the land rises or falls relative to the sea
● This leads to coasts which are either emergent or submergent
Short Term Processes
● Coasts can also be categorised by short term factors:
○ Waves - can be constructive or destructive
○ Tides - tidal range is the difference between high and low tide
○ Rivers
○ Storm events
● These create coastlines that can be:
○ Retreating or advancing which depends on whether erosion or
deposition dominates
○ Dominated by land based processes (primary coasts) or marine
processes (secondary coasts)
○ Large or small tidal range
○ High or low energy
Characteristics of High and Low Energy Coasts
High Energy Coasts Low Energy Coasts
● Destructive waves ● Constructive waves
● Exposed to strong winds and ● Sheltered locations with short
long fetches fetch
● Higher rates of erosion than ● Higher rates of deposition than
deposition erosion
● Tend to be rocky coasts ● Sandy beaches, salt marshes,
● Steep cliffs - marine cliff profile estuarine and tidal mud flats
● Less steep cliffs - subaerial cliff ● Gentle relief
profile ● Sediment from land and sea
● Headlands, wave cut platforms ● Beaches, spits, coastal plains
Rocky Coasts
, ● Rocky coasts form where there is more resistant geology - in the UK this is
mainly in the north and west of the country
● Cliffs of varying heights and steepness can be found along rocky coastlines:
○ Steep cliffs tend to be found in high energy environments
○ Cliffs with a gentler slope tend to be found in low energy environments
● Erosion is more dominant than deposition
● Two types of erosion may dominate along rocky coastlines:
○ Marine erosion - the action of waves
○ Sub-aerial erosion - weathering and mass movement
Coastal Plain Landscapes
● Coastal plains usually occur where the land gradually slopes down towards
the sea
● Tend to be low relief
● Coastal plains include both:
○ Sandy coastlines
○ Estuarine coastlines
● These are usually low energy coastal environments
● They form due to coastal accretion - when deposition is greater than erosion
● Sediment for deposition comes from:
○ Offshore sources
○ Terrestrial sources
● Dunes form, helping to stabilise the coast and reduce erosion
● Wetlands and marshes form due to poor drainage
● Estuarine coastlines form at the mouths of rivers and are formed from clay
and silt
Discordant & Concordant Coast Formation
Discordant coastlines
● A discordant coastline is one where the rock structures meet the coast at an
angle - run perpendicular to oncoming waves
● Alternating rock types lead to the formation of headlands and bays
● Discordant coasts are also known as Atlantic coasts
Concordant coastlines
● Concordant coastlines are where the rock structures run parallel to the coast
● Dalmatian and Haff coastlines are examples of concordant coastlines
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