Topic 2b – Coasts
,2B.1a - The Littoral Zone
Littoral zone – boundary between land + sea. It is a zone rather than a line because tides and
storms affect a band around the coast. It varies due to LT + ST factors, and is divided into 4
sections;
1. Backshore – above the influence if waves
2. Foreshore – inter tidal surf zone
3. Nearshore – breaker zone
4. Offshore – beyond the influence of waves
- Greatest human activity occurs + physical processes of erosion, deposition,
transportation + mass movement in backshore and foreshore zones.
Example of event occurring at littoral zone: Charmouth, Dorset
• December 2015 a big rockfall occurred where 100m of cliff fell onto charmouth beach.
It exposed fresh blocks of mud and shale which revealed fossils
The littoral zone forms three types of coastal landscape:
1. Rocky, cliffed coastline
- areas of high relief varying from a few metres to hundreds of metres in height
- usually form in areas with resistant geology, in a high energy environment, where
erosion is greater than deposition and big, stormy destructive waves
2. Sandy coastline
- areas of low relief with sand dunes and beaches, that are much flatter.
- they usually form in areas with less resistant geology, low energy environment,
where deposition > erosion + constructive waves
3. Estuarine coastline
- Areas of low relief with salt marshes and mudflats (estuaries)
- They form in river mouths where deposition > erosion, in a low energy environment
usually in areas of less resistant rock
,The littoral zone is a dynamic zone of rapid change, this means that there are constantly
changing inputs, through flows, and outputs of energy and material (short term).
There are also long-term changes, e.g. sea level variation due to climate change +
short-term changes e.g. high and low tide variation over the lunar month; wave energy variation
due to weather conditions.
2B.1b - Classifying coasts
(open system as it receives inputs from outside the system and transfers outputs away from the
coast and into other systems)
Long term criteria Short term criteria
Geology Energy inputs
All characteristics of land including lithology From waves, tides, fetch. Currents, rivers,
+ structure is used to classify coasts as tectonics, atmospheric processes. High/low
rocky/sandy/estuarine or energy
concordant/discordant
Sea level change Sediment inputs
Used to classify coast as emergent or Coasts receive SI from waves, tides, winds,
submergent, can be caused by tectonic currents, MM + tectonic processes. If erosion
processes or climate change > deposition = net loss of sediment +
coastline retreats. If opposite = net gain of
sediment
Advancing/retreating
Coastlines are classified as advancing or
retreating due to LT + ST processes
2B.1C - Rocky coasts and coastal plains
Rocky coast - usually from in areas of geology that is resistant to the erosive forces of the sea
rain + wind. Lithology/structure means that they erode slower. They form in high energy
environments where erosion > deposition. Rocky coasts occupy about 1,000 km of the UK's
coastline, mainly in the north and west. Cliffs vary in height from high-relief areas, e.g. 427m
Cona chair Cliff on the Isle of Hirta in the Outer Hebrides to low relief. 3m cliffs at Chapel Porth
in Cornwall.
Coastal Plains - (sandy and estuarine coastlines) e.g. The Wash
• Coastal plain landscapes are relatively flat, low relief areas adjacent to the sea.
• They often contain freshwater wetlands and marshes due to the poor drainage of the flat
landscape.
• Their littoral zone is composed of sand dunes, beaches, mud flats and salt marshes.
• Form in low-energy environments where deposition > erosion, so they experience a net
accumulation of sediment.
, • They form through coastal accretion (a continuous net deposition of sediment.) This
comes from: offshore sources (transported by waves, tides or current) and terrestrial
sources (transported by rivers, glaciers, wind or mass movement)
• May be sandy coasts, composed of sands, shingles and cobbles or estuarine (alluvial)
coasts composed of mud (clays and silts)
Coastal Plain Formation
• They usually form by coastal accretion, where continuous net deposition causes the
coastline to extend seawards. This is often extended biologically as plants colonise
shallow water, trapping sediment and forming organic deposits when they die.
• They also form by sea level change, when the falling sea level exposes a flat continental
shelf. e.g. the Atlantic coastline of the USA.
• Where erosion = deposition dynamic equilibrium exists as there's a continuous flow of
energy and material through the coasts, but the size of stores (beach, salt marsh,
mudflat) remains unchanged.
Luskentyre Peninsula – Scotland Bedruthan Steps
High levels of rainfall Facing W
Cold temp in winter = freeze thaw Wavecut platform
Tropical looking Resistant rock
SW facing
Resistant metamorphic rock
Bamburgh Beach Mudflats
Carboniferous limestone Facing east
Dunes and grass Clay and sandstone
High energy coastline Low energy coastline
Rate of erosion > deposition rate Sandy and estuarine coasts are found here
Erosional landforms e.g. headlands, cliffs + which tend to be waves less powerful or the
shoreline platforms found here coast is sheltered
Rocky coasts found here + stretches of Deposition > erosion
Atlantic facing coasts where waves are Landforms like beaches, spits and plains are
strong found here
Coast as a system
Marine – waves, tides, storm surges
Atmospheric – weather/climate/change INPUTS
Land – rock type/structure, tectonic activity
People – human activity, coastal management
,2B.1a - The Littoral Zone
Littoral zone – boundary between land + sea. It is a zone rather than a line because tides and
storms affect a band around the coast. It varies due to LT + ST factors, and is divided into 4
sections;
1. Backshore – above the influence if waves
2. Foreshore – inter tidal surf zone
3. Nearshore – breaker zone
4. Offshore – beyond the influence of waves
- Greatest human activity occurs + physical processes of erosion, deposition,
transportation + mass movement in backshore and foreshore zones.
Example of event occurring at littoral zone: Charmouth, Dorset
• December 2015 a big rockfall occurred where 100m of cliff fell onto charmouth beach.
It exposed fresh blocks of mud and shale which revealed fossils
The littoral zone forms three types of coastal landscape:
1. Rocky, cliffed coastline
- areas of high relief varying from a few metres to hundreds of metres in height
- usually form in areas with resistant geology, in a high energy environment, where
erosion is greater than deposition and big, stormy destructive waves
2. Sandy coastline
- areas of low relief with sand dunes and beaches, that are much flatter.
- they usually form in areas with less resistant geology, low energy environment,
where deposition > erosion + constructive waves
3. Estuarine coastline
- Areas of low relief with salt marshes and mudflats (estuaries)
- They form in river mouths where deposition > erosion, in a low energy environment
usually in areas of less resistant rock
,The littoral zone is a dynamic zone of rapid change, this means that there are constantly
changing inputs, through flows, and outputs of energy and material (short term).
There are also long-term changes, e.g. sea level variation due to climate change +
short-term changes e.g. high and low tide variation over the lunar month; wave energy variation
due to weather conditions.
2B.1b - Classifying coasts
(open system as it receives inputs from outside the system and transfers outputs away from the
coast and into other systems)
Long term criteria Short term criteria
Geology Energy inputs
All characteristics of land including lithology From waves, tides, fetch. Currents, rivers,
+ structure is used to classify coasts as tectonics, atmospheric processes. High/low
rocky/sandy/estuarine or energy
concordant/discordant
Sea level change Sediment inputs
Used to classify coast as emergent or Coasts receive SI from waves, tides, winds,
submergent, can be caused by tectonic currents, MM + tectonic processes. If erosion
processes or climate change > deposition = net loss of sediment +
coastline retreats. If opposite = net gain of
sediment
Advancing/retreating
Coastlines are classified as advancing or
retreating due to LT + ST processes
2B.1C - Rocky coasts and coastal plains
Rocky coast - usually from in areas of geology that is resistant to the erosive forces of the sea
rain + wind. Lithology/structure means that they erode slower. They form in high energy
environments where erosion > deposition. Rocky coasts occupy about 1,000 km of the UK's
coastline, mainly in the north and west. Cliffs vary in height from high-relief areas, e.g. 427m
Cona chair Cliff on the Isle of Hirta in the Outer Hebrides to low relief. 3m cliffs at Chapel Porth
in Cornwall.
Coastal Plains - (sandy and estuarine coastlines) e.g. The Wash
• Coastal plain landscapes are relatively flat, low relief areas adjacent to the sea.
• They often contain freshwater wetlands and marshes due to the poor drainage of the flat
landscape.
• Their littoral zone is composed of sand dunes, beaches, mud flats and salt marshes.
• Form in low-energy environments where deposition > erosion, so they experience a net
accumulation of sediment.
, • They form through coastal accretion (a continuous net deposition of sediment.) This
comes from: offshore sources (transported by waves, tides or current) and terrestrial
sources (transported by rivers, glaciers, wind or mass movement)
• May be sandy coasts, composed of sands, shingles and cobbles or estuarine (alluvial)
coasts composed of mud (clays and silts)
Coastal Plain Formation
• They usually form by coastal accretion, where continuous net deposition causes the
coastline to extend seawards. This is often extended biologically as plants colonise
shallow water, trapping sediment and forming organic deposits when they die.
• They also form by sea level change, when the falling sea level exposes a flat continental
shelf. e.g. the Atlantic coastline of the USA.
• Where erosion = deposition dynamic equilibrium exists as there's a continuous flow of
energy and material through the coasts, but the size of stores (beach, salt marsh,
mudflat) remains unchanged.
Luskentyre Peninsula – Scotland Bedruthan Steps
High levels of rainfall Facing W
Cold temp in winter = freeze thaw Wavecut platform
Tropical looking Resistant rock
SW facing
Resistant metamorphic rock
Bamburgh Beach Mudflats
Carboniferous limestone Facing east
Dunes and grass Clay and sandstone
High energy coastline Low energy coastline
Rate of erosion > deposition rate Sandy and estuarine coasts are found here
Erosional landforms e.g. headlands, cliffs + which tend to be waves less powerful or the
shoreline platforms found here coast is sheltered
Rocky coasts found here + stretches of Deposition > erosion
Atlantic facing coasts where waves are Landforms like beaches, spits and plains are
strong found here
Coast as a system
Marine – waves, tides, storm surges
Atmospheric – weather/climate/change INPUTS
Land – rock type/structure, tectonic activity
People – human activity, coastal management
