lesson 4+5-processes Flashcards
what are marine processes
the wearing away of the land surface and removal of materials by river and sea water, ice and wind
-operate on the coastline, connected to the sea
what are sub aerial processes
the decay and disintegration of rock
-operate on land, but affect the shape of the coast e.g. weathering, mass movement
what is the rate of coastal erosion affected by
-wave steepness and breaking point
-fetch- how far the wave travels
-sea depth
-coastal configuration
-beaches
-human activities
what type of waves form rocky beaches
destructive
what type of waves form sandy beaches
constructive
what is a concordant coastline
coastline is one rock
what is a discordant coastline
coastline is multiple layers of rock
what is marine deposition
areas of low wave energy or rapid coastal erosion provide an abundance of material
-sand and shingle accumulate faster than they are removed
-waves slow after breaking
-waves pause at the top of the swash
-water peculates into the beach before running back down
what is aeolian deposition
entrainment (carry in air), transport and deposition of material by wind
-at low tide sand is exposed, so it is entrained and transported via surface creep or saltation
what is freeze thaw
water seeps into cracks in rocks and then freezes, expanding and causing the cracks to widen
what is pressure release
disintegration of rock in parallel sheets as it expands in response to the removal of confining stress
what is biological weathering
animals or plants can burrow drill or move material
what is acid rain
sulphur dioxide + nitric acid combine with raindrops, weaken rocks
what is carbonation
CO2 dissolves in rainwater and reacts with limestone and chalk
what does the nature of mass movement depend on
-The level of cohesion within the sediment
-Height of the slope and slop angle
-Grain size within the sediment
-Temperature
-Level of saturation.
what is a landslide
on steep cliffs made from softer rock or deposition which slips when lubricated, usually following heavy rainfall.
what is a mudflow
heavy rain causes large quantities of fine material to flow down the slope.
On gentle slopes, the slower flow is often referred to as ‘solifluction’
what is rotational slip / slumping
when softer material overlies more resistant material. With excessive lubrication, whole sections of the cliff may move downwards with a slight plane that is concave.
