Coasts
Explain formation of Fjords
- Submergence
- Primarily product of glacial erosion
- Glaciers advancing to sea carved by glacial troughs through
abrasion and plucking.
- E.g. Sogne Fjord (Norway)
- Unlike rias they are not deepest at the mouth
- Through isostatic readjustment and eustatic sea level change they
flood the valleys
Explain formation of drift aligned beaches.
- Parallel to direction of dominant LSD
- Carry large volumes of sediment.
- Waves are at a significant angle to the beach.
- Carries larger volumes of sediment at the start, gets finer.
- Can lead to formation of spits.
Explain formation of salt marshes
- Develop in sheltered estuaries behind spits.
- Silt deposited by river gradually building intertidal mudflat.
- Continues to rise above sea level as more silt is deposited.
- Halophytic veg (highly adapted to env) colonises the mud flat,
trapping more sediment.
Associated environments that saltmarshes develop.
1. Sheltered waters (lee of spit) e.g. Key haven saltmarsh – sheltered
by Hurst castle spit.
2. Convergence of saltwater and freshwater (brackish) e.g. commonly
found on the Medway peninsular along the river Thames.
3. Where there are no strong tides or currents to prevent deposition
Features of concordant coastline
, - Rock type and structure runs parallel to coast.
- Smooth coastline
- Few headlands and bays
- Coastline has similar shape and features across its length.
- Uniform rate of erosion
- E.g. Algarve coast Portugal
Features of discordant coastline
- Rock type and structure runs perpendicular to coast.
- Varying rock resistance to erosion creates diverse range of
landforms.
- Many bays, headlands, and other irregular features
- E.g. Coast of Brittany (France)
Features of swash aligned beaches.
- Parallel to incoming wave crests
- Experiences minimal LSD
- Sediment can’t travel far on beach.
- Wave refraction can decrease speed and form shingle beach with
larger sediment.
Compare berms and cusps.
- Berm = large beach ridge formed by constructive waves
- Cusps = Small curved dips. Semi-circular shaped depressions
forming when waves break. Occur at junction of shingle and sandy
beach. Waves have both strong swash and backswash.
Outline stages of sea level change
1. Eustatic
2. Isostatic
3. Climate warms – submergent features e.g. Fjords.
4. Isostatic readjustment
Benefits of mangroves
, - Wood, valuable source of timber and fuel
- Coastal protection, 1ha has econ value of $12,000, 5x more
effective than ‘grey’ infrastructure.
- Carbon storage, 3-5x higher than tropical upland forest
- Ecotourism
- Fisheries, over 3000 fish species
- Dense roots bind and build soils.
Explain formation of Ria
- Submergent
- Drowned river valley
- Sea levels rise leaving only high land visible e.g. apparent in
Falmouth, Cornwall
- Long section and cross profile
- Dendritic drainage system
- E.g. Milford Haven
Raised beaches features.
- Area of former WCP
- Higher than present sea level
- Common in Scotland, Isle of Arran (think loyle carner)
Describe a halosere succession.
- Series of communities displaying a successional sequence where
plants are adapted to saltwater.
- Env characterised by saline conditions.
- Specially adapted plants and animals
- Low energy coastline, behind bars and spits
- Silt deposited allowing salt tolerant plants to develop.
Explain the process of flocculation.
- Soil particles sticking together.
- Occurs in brackish water.
- When clumped enough, mass increases, sinking them to bottom of
riverbed.
- Otherwise, clay particles are so fine they may never settle.
Features of halophytes
Explain formation of Fjords
- Submergence
- Primarily product of glacial erosion
- Glaciers advancing to sea carved by glacial troughs through
abrasion and plucking.
- E.g. Sogne Fjord (Norway)
- Unlike rias they are not deepest at the mouth
- Through isostatic readjustment and eustatic sea level change they
flood the valleys
Explain formation of drift aligned beaches.
- Parallel to direction of dominant LSD
- Carry large volumes of sediment.
- Waves are at a significant angle to the beach.
- Carries larger volumes of sediment at the start, gets finer.
- Can lead to formation of spits.
Explain formation of salt marshes
- Develop in sheltered estuaries behind spits.
- Silt deposited by river gradually building intertidal mudflat.
- Continues to rise above sea level as more silt is deposited.
- Halophytic veg (highly adapted to env) colonises the mud flat,
trapping more sediment.
Associated environments that saltmarshes develop.
1. Sheltered waters (lee of spit) e.g. Key haven saltmarsh – sheltered
by Hurst castle spit.
2. Convergence of saltwater and freshwater (brackish) e.g. commonly
found on the Medway peninsular along the river Thames.
3. Where there are no strong tides or currents to prevent deposition
Features of concordant coastline
, - Rock type and structure runs parallel to coast.
- Smooth coastline
- Few headlands and bays
- Coastline has similar shape and features across its length.
- Uniform rate of erosion
- E.g. Algarve coast Portugal
Features of discordant coastline
- Rock type and structure runs perpendicular to coast.
- Varying rock resistance to erosion creates diverse range of
landforms.
- Many bays, headlands, and other irregular features
- E.g. Coast of Brittany (France)
Features of swash aligned beaches.
- Parallel to incoming wave crests
- Experiences minimal LSD
- Sediment can’t travel far on beach.
- Wave refraction can decrease speed and form shingle beach with
larger sediment.
Compare berms and cusps.
- Berm = large beach ridge formed by constructive waves
- Cusps = Small curved dips. Semi-circular shaped depressions
forming when waves break. Occur at junction of shingle and sandy
beach. Waves have both strong swash and backswash.
Outline stages of sea level change
1. Eustatic
2. Isostatic
3. Climate warms – submergent features e.g. Fjords.
4. Isostatic readjustment
Benefits of mangroves
, - Wood, valuable source of timber and fuel
- Coastal protection, 1ha has econ value of $12,000, 5x more
effective than ‘grey’ infrastructure.
- Carbon storage, 3-5x higher than tropical upland forest
- Ecotourism
- Fisheries, over 3000 fish species
- Dense roots bind and build soils.
Explain formation of Ria
- Submergent
- Drowned river valley
- Sea levels rise leaving only high land visible e.g. apparent in
Falmouth, Cornwall
- Long section and cross profile
- Dendritic drainage system
- E.g. Milford Haven
Raised beaches features.
- Area of former WCP
- Higher than present sea level
- Common in Scotland, Isle of Arran (think loyle carner)
Describe a halosere succession.
- Series of communities displaying a successional sequence where
plants are adapted to saltwater.
- Env characterised by saline conditions.
- Specially adapted plants and animals
- Low energy coastline, behind bars and spits
- Silt deposited allowing salt tolerant plants to develop.
Explain the process of flocculation.
- Soil particles sticking together.
- Occurs in brackish water.
- When clumped enough, mass increases, sinking them to bottom of
riverbed.
- Otherwise, clay particles are so fine they may never settle.
Features of halophytes
