Coasts EQ2 Flashcards
What are constructive waves?
Powerful wave with strong swash that surges up a beach
Deposits material, doesn’t remove any
Generated far offshore
Elliptical water movement, low amplitude and gentle gradient
What are destructive waves?
Waves formed by local storm that crash on the beach
Powerful backwash, remove material from the beach
Create steep beach profile
What is hydraulic action?
Waves force air into cracks and trap it causing cracks in rocks breaking it down
What is abrasion?
Loose material is thrown at coastline breaking it down
What is attrition?
Loose material collides together becoming smaller and rounder
What is corrosion?
Chemical breakdown of some rocks
Very common in limestone where it slowly dissolves
Examples of erosional landforms?
Caves
Stacks
Stumps
Arches
Wave cut platform
Wave cut notch
What is long shore drift?
Lateral transport of material along coastline when waves approach coast at an angle
What is a swash aligned beach?
Waves arrive parallel to beach so sediment deposited
What is drift aligned beach?
Waves break at angle to the coast so material transported and dropped by long shore drift
What is gravity settling?
Waves energy of transporting become too low to move sediment so deposits material
Large sediment dropped first
What is flocculations?
Depositional process- small particles like clay clump together so they become large enough to sink
What is a spit?
Extended stretch of beach
Prevailing winds continues LDS past end of beach
LDS stops when second prevailing wind hits and looses energy
Can cause a curve
What is a bay head beach?
Curved beaches found at back of a bay
Common on swash aligned beaches
Wave refraction distributes wave energy at bay perimeter dropping sediment
What is a tombolo?
Formed by spit connecting 2 headlands together
Creates lagoon behind it
What is a barrier beach?
Formed by LDS connecting offshore island to mainland
Protection from island causes deposition
What is recurved spit?
Formed same way as spit
Forms salt marshes behind sometimes
What is a cuspate foreland?
LSD either side of headland continues up and meets causing triangular beach
What is the sediment cell concept?
Self contained stretch of coast
Means sediment moves around a cell but not from one to another
11 in England and wales
What are sub aerial processes?
Weathering and mass movement
What is physical/mechanical movement?
Breaking down of larger rocks into smaller rocks
Freeze thaw action
What is biological weathering?
Disintegration of rocks due to actions of plants/animals
Roots growing into rocks
Burrowing
What is chemical weathering?
Chemical reaction occurs in the rock causing it to dissolve and form new substances
Carbonation
What is rockfall?
Sudden form of mass movement
Occurs when fragments of rock weathered from cliff fall under gravity and collect at base
What is a landslide?
Sea wars dipping strata present and heavily jointed rocks susceptible
Eg limestone
What is a mudslide?
unconsolidated sediment saturated with water
What is slumping?
bottom of cliff eroded by waves, slope becomes steeper and cliff slides down in rotational manner
often triggered by rain
What is a landslide scar?
mark left on cliff profile from the landslide
What is terraced profile?
where a cliff profile is stepped due to lithology or fractures in the rock
