Coastal Landscapes Flashcards
Define Coastal Landscapes
-the whole coastline
Define Coastal Landform
-Individual components of the landscape
What is a concordant coastline
-waves are parallel to the layers of rock
What is a discordant coastline
-Waves are perpendicular to the coastline
What does a concordant coastline produce and explain how
- It creates coves and islands along the coast line
- Erode joins/faults at the hard rock
- Soft rock easier to erode
- Creates a cove - hollows out
- LULWORTH COVE
What does a discordant coastline produce
- Creates headlands and bays
- Hard rock harder to erode
- Soft rock easier to erode
- East Purbeck Coast
What is a wave cut platform
- angle of fewer than 5 degrees
- FOUND IN INTERTIDAL ZONE
- waves focus erosion in the intertidal zone
- leads to wave-cut notch
- wave-cut notch grows
- cliff retreats
- abrasion on the surface
- gently sloped platform of rocks left behing
What is a blowhole
- Verticle hole is eroded above a cave - once filled with water, water gets blown up and through like a jet
- Overlying rock in a cave collapses
- Erosion continues vertically
What is a Geo
- Cracks and joints get attacked repeatedly making a narrow long inlet in a cliff
- either formed from erosion or blowhole collapse
What is needed for depositional landforms
-sediment surplus - gain more than loss
What are the different types of beaches
- swash aligned
- drift aligned
What is a swash aligned beach
-Beaches are parallel to the coastline - concave beaches - no longshore drift
What is a drift aligned beach
- beaches are produced where the waves are at an angle to the beach
- There is longshore drift taking place here
What is a berm
- Ridges made at the back of the beach
- created from successive high tides
- constructive waves
What is a storm beach
-strong swash or hightide
What is a ridge
-ridges of sand parallel to the coastline
What is a ridge
-channels of water - they drain water off the beach
What is a longshore bar (offshore bar)
- submerged or partially submerged ridges of sand
- formed by destructive waves with strong backwash
- absorb wave energy
What is a spit
- Depositional landform
- compound or simple
- made up of shingle and sand
- curved end - DISTAL END
- start - PROXIMAL END
How is a spit formed
- drift aligned beach
- Change in direction of the coastline
- The heavy material (shingle) is deposited first
- This continues to happen until it reaches an estuary - the current stops deposition
- A salt marsh is formed behind
What is an offshore bar
- Submerged or partially exposed ridge of sand created by waves
- Appears at the breaking of a wave
- Destructive waves erode sand from the beach
- Strong backwash deposits at the offshore bar
What is a barrier beach
- where a spit extends across a bay to join two headlands
- Forned if the spit continuing
- formed during peirod of high water level of a storm or high tide season
- Drift alligned shore
What is a barrier island
- Continous growth of an offshore bar to create an island
- Strong backwash creates a bar
- occurs repeatidly
- offshore bar grows
- Creates a lagoon with calm muddy water - mangrove forest
- Lagoon is sheltered
What is a tombolo
- an island is joined to the mainland by a tombolo
- If a longshore current is pushed by a prevailing wind behind an island (wave shadow) - a tombolo forms
- if a spit connects an island to the mainland - the spit continues and extends out to the island
