Section C - Coastal Landscapes In The UK Flashcards
What are constructive waves? Give a few characteristics of these waves
These are low waves that surge up the beach and spill with a powerful swash. They carry and deposit large amounts of sand and pebbles and construct the beach, making it more extensive
What are destructive waves? Give a few characteristics of these waves
These are formed by local storms close to the coast and they can destroy the beach. They are closely spaced and often interfere with each other
What is the fetch
When friction with the sea surface creates waves. The longer the fetch the more powerful the waves
What are waves
Bulges of water moving in a cyclical motion. Waves come into contact with the sea bed
What are the 5 steps of waves approaching the coast
1) circular orbit in open water
2) friction with the sea bed distorts the circular orbital motion
3) increasingly elliptical orbit, top of wave moves faster
4) wave begins to break
5) water from previous wave returns, water rushes up the beach
What happens at beachy head, 2001 at rockfall
During the wet winter of 2000, the chalk rock became saturated with water. The water froze during the winter. In April 2001, this caused a rockfall.
What causes cliffs to collapse
Cliffs collapse because of different types of weathering. This is the weakening or decay of rocks in their original place on, or close to the ground surface. it is mostly caused by weather
What is mechanical weathering (physical)
the distintegration (break up) of rocks. where this happens piles of rock fragments called SCREE can be found at the foot of cliffs
what is chemical weathering caused by
caused by chemical changes - rainwater, which is slightly acidic, very slowly dissolves certain types of rocks and minerals
what is biological weathering caused by
caused by the actions of flora and fauna. plant roots grow in cracks in the rocks. animals such as rabbits, burrow into weak rocks such as sands
how does freeze thaw weathering happen (mechanical)
1) water collects in cracks or holes (pores) in the rock
2) at night this water freezes and expands and makes cracks in the rock bigger
3) when the temperature rises and the ice thaws, the water will seep deeper into the rock
4) after repeated freezing and thawing, fragments of rock may break off and fall to the foot of the cliff (SCREE)
how does salt weathering happen (mechanical)
1) sea water contains salt. whem the water evaporates it leaves behind salt crystals
2) in cracks and holes these salt crystals grow and expand
3) this puts pressure on the rocks and flakes may eventually break off
how does carbonation weathering happen (chemical)
1) rainwater absorbs C02 from the air and becomes slightly acidic
2) contact with alkaline rocks such as chalk and limestone produces a chemical reaction causing the rocks to slowly dissolve
what is mass movement
the downward movement or sliding of material under the influence of gravity
what happened in 1993 (mass movement)
60 metres of cliff slipped onto the beach near Scarbourough in North Yorkshire taking with it part of the Holbeck Hall Hotel
what is rockfall
when fragments of rock break away from the cliff face, often due to freeze thaw weathering
what is a landslide
when blocks of rock slide downhill
what is mudflow
when saturated soil and weak rock flows down a slope
what is rotational slip
slump of saturated soil and weak rock along a curved surface
what does coastal erosion involve
the removal of material and the shaping of landforms
what is the process of solution
EROSION
the dissolving of soluble chemicals in rocks e.g. limestone
what is the process of corrasion
EROSION
fragments of rock are picked up and hurled by the sea at a cliff
what is the process of abrasion
EROSION
the sandpapering effect of pebble grinding over a rocky platform, often causing it to become smooth
what is the process of hydraulic power
EROSION
the power of the waves as they smash onto a cliff
what is the process of attrition
EROSION
rock fragments carried by the sea knock against one another causing them to become smaller and more rounded
what is solution
TRANSPORTATION
dissolved chemicals ofter derived from limestone or chalk
what is suspension
TRANSPORTATION
particles carried (suspended) within the water