coasts Flashcards
(82 cards)
what type of wave has a weak swash but strong backwash?
destructive wave
what does a strong backwash do?
remove sediment from the beach
in what type of wave are the waves steep and close together?
destructive wave
what type of wave has a strong swash but weak backwash?
constructive wave
what does the swash do to the beach in a constructive wave?
brings sediment up the beach
what type of wave has low and far apart waves?
constructive wave
what is the swash?
water that rushes up the beach
what is the backwash?
water that flows back to the sea
what is the fetch of a wave?
how far the wave has travelled
what 3 things does the size and energy of a wave depend on?
the fetch, the strength of the wind, how long wind has been blowing for
what does the rock have to be in order for freeze-thaw weathering to occur?
porous or permeable
explain the steps of freeze-thaw weathering
- water enters cracks in rock
- temps drop and water freezes and expands causing crack to widen
- ice melts and goes deeper into cracks in rock
- process repeats until rock splits entirely
explain the steps of biological weathering
- plant roots can get into small cracks in rock
- they grow and cracks get larger
- small pieces of rock breakaway
explain chemical weathering
rain + seawater can be a weak acid. overtime rocks can become dissolved by the acid in the water
what 2 types of rock are prone to chemical weathering?
limestone and chalk
what is mass movement?
the downhill movement of sediment that moves because of gravity
what is rockfall?
when bits of rock fall off the cliff face usually due to freeze thaw weathering
what is mudflow?
when saturated soil flows down a slope
what is landslide?
when large blocks of rock slide downhill
what is rotational slip?
when saturated soil slumps down a curved surface
what type of wave is responsible for erosion on the coastline?
destructive
what is hydraulic action?
the sheer power of the waves, air becomes trapped in cracks in rock and causes it to breakaway