Coasts Flashcards
What is carbonation
Where rainwater reacts with limestone and chalk and dissolves them (form of chemical weathering)
Water reacts with carbon dioxide in air to form carbonic acid (rainwater) which is what reacts with the sedimentary rock
Compare different types of mass movement
Landslide- large blocks of sediment/ rock slide downhill
Rock fall- small loose pieces of rock fall off cliff
Slumping- saturated soil moves downwards over curved surface
Mudflow- saturated soil flows downhill
Describe longshore drift
The prevailing wind causes sediment to be carried towards the beach at an angle by the swash.
The backwash then brings the sediment straight back out to sea. This process repeats itself so that sediment is transported along the beach in a zig zag motion by traction (until the sea eventually runs out of energy and the sediment is deposited)
Attrition occurs along the way making the pebbles smaller and rounder
Describe sand dune formation process
Sand dunes are formed on a large sandy beach (caused by a large tide range so at low tide there is a large beach) where there are sheltered conditions so that a constant supply of sand can be added to the beach by constructive waves (or via longshore drift if a nearby coastline is being eroded)
There also needs to be a prevailing wind and periods of time when the exposed beach dries out
As sand moves up the beach via saltation, debris leg flotsam and jetsam traps it in place to prevent it from blowing away so that the sand can be deposited and starts to develop into an embryo dune
The embryo dune then becomes an obstacle for more dunes to form behind it
How dunes change
Goes from embryo to fore to yellow to mature
Get bigger and bigger except mature where supply of sand runs out so no more sand can be deposited
Ph decreases
Nutrient levels increase
Level of Vegetation increases
Biodiversity increases
