landscapes of the uk Flashcards
what are the three rock types and how were they formed?
Igneous - forms deep within the earth from magma
metamorphic - are formed when either Igneous or sedimentary rocks are changed by pressure or heat.
sedimentary - made using erosion processes
destructive wave
- short wave length, high frequency
- wave height over 1 meter
- weak swash (because wave smashes downwards into slope so does not go far up the beach)
- strong backwash
constructive wave
- long wave length, low frequency
- strong swash
- weak backwash
- low wave under 1 meter
Hydraulic action occurs when …
waves crash into cracks in the rocks and the compressed air exerts lots of pressure on the rock
abrasion occurs when ….
waves throw pieces of small rock and sediment into the cliff face to erode it
solution occurs when. …..
soluble rocks are dissolved in the ocean like chalk
what is freeze thaw weathering
its when water gets into the cracks in rocks and expands when frozen meaning pressure is exerted on the rock
what is a rotational slump ?
saturated soil falls down a curved cliff face due to gravity
explain longshore drift
the prevailing wind pushes the waves up the beach. the sediment is carried diagonally across up the swash, and straight back in the backwash due to gravity. the sediment is gradually carried along the beach.
what is traction and saltation
traction - large rocks being rolled and worn down on the river/ sea bed
saltation - smaller rocks same process
how was old harry formed ?
- the cracks in old harry were worn down by hydraulic action
- the cracks got bigger eventually creating an arch
- eventually the arch become to heavy and falls into the sea, leaving a stack and eventually a stump
- the process then repeats and another old harry will form
name 4 coastal defences
- revetments
- groynes
- beach replenishment
- sea wall
- gabions
