Coasts Quick Facts Flashcards
From week 4 (17 cards)
What is attrition
Beach material knocked together in the water reducing size and increasing roundness and smoothness
What is abrasion
Sediment picked up by breaking waves is thrown against the cliff face acting like sandpaper
What is hydraulic action
The wave power eroding the sediment. When a wave hits a cliff, air is forced into cracks under high pressure, widening cracks
What is solution/corrosion
Seawater and salt spray from waves may react with rock minerals to dissolve them
How is a crack in a cliff formed
Opened up by hydraulic action which pressurised air, causing crack to widen
Further widened by weathering and crystallisation
How does a crack in a cliff grow
Grows into a cave by hydraulic action and abrasion
How do caves grow
Wave refraction destorts the wave direction, causing destructive waves to concentrate on the headland
How are natural arches formed
Cave breaks through headland
Especially if 2 caves are aligned back to back
Wave cut notches widen the base
How are stacks formed
Arch collapses and stack eroded more by wave cut notches
Sub ariel processes weaken it from above
How are stumps eroded
By hydraulic action and abrasion
What influences the size of a wave
Water depth
Fetch (distance the wave has travelled)
Wind speed
Time the wind blows for
How does strata work?
Sedimentry rocks that have been laid down in distant strata may dip towards the sea or away from it
This presents either a smooth surface towards the sea or a rough broken surface. A smooth surface will better resist waves than a broken one.
How can an equilibrium be maintained
Negative feedback
What is a bar
A spit that joins toagther 2 headlands. Bars are particularly obvious at low tide when they become exposed
How might a lagoon form
In a bay as a result of a bar
Where is a tombolo formed
Where a spit links the mainland and an island
What can lagoons get infilled with
Salt marsh
