Coastal Environments Flashcards
What is a coast?
The transition zone between land and sea
What are factors that affect coasts?
Wind,tsunamis, tide and humans
How is a wave created?
When wind is blown over the surface of the sea/ocean, creating friction
What are the three factors that affect wave size?
Speed of wind, duration the wind is bowing for, length of fetch
What is fetch?
The length of water the wind blows over
What is swash?
The transfer of the waves energy up a beach in the direction the wind blows
What is backwash?
The transfer of the wave’s energy down the beach at a right angle to the beach due to gravity
When are destructive waves formed?
In stormy conditions with high winds
Characteristics of destructive waves
High wave height, short wave length, backwash is stronger than swash, frequent (11-15 per min), steep beach gradient
When are constructive waves found?
In calm conditions
Characteristics of constructive waves?
Long wave length, low wave height, swash stronger than backwash, 6-9 per min frequency, gentle beach gradient
What is a marine process?
A process that occurs in the sea
What are the three marine processes?
Erosion, transportation, deposition
What happens with deconstructive waves?
Erosion
What happens with constructive waves?
Deposition
What is erosion
The wearing away of rocks, stones and soil by rivers, waves, wind and glaciers
What are the factors that affect erosion?
Geology (hard/soft rock), vegetation (plants can help bind a cliff together), human activity, climate change (rising sea levels=more storms=more erosion)
What is hydraulic action?
When waves break at the bottom of cliffs and squash air into the cracks in the rock. This causes a blast as the wave moves back and air pressure is suddenly released. Chunks of rock crash off the cliff.
Which type of wave will have more hydraulic action?
Deconstructive
When there a higher tides what happens to the hydraulic action?
Higher hydraulic action
What is attrition?
When pebbles moving around in the sea collide into each other. Over time this impact wears away the jagged edges to make smooth rounded pebbles.
What does attrition create?
Sand
What is abrasion?
When destructive waves throw sand and shingle at a cliff. This scrapes and scratches the rock surface
What is solution/corrosion?
When sea water dissolves certain types of rocks.
Which style of cliffs are prone to solution/corrosion?
Akali rocks such as Chalk and limestone
Why does solution/attrition occur?
Because seawater is slightly acidic
What is transportation?
Sediment being moved in powerful water
What are the 4 types of erosion?
Hydraulic action, attrition, abrasion, solution/corrosion?
What are the 4 types of transportation?
Traction, saltation, suspension, solution
What is traction?
When larger stones and rocks get rolled along
What is saltation?
When sand grains and small stones bounce along
What is solution?
When material eroded by acidic sea water can be moved a solute. OR material dissolved by rainwater
What is suspension?
When small particles of rock and soil are carried along as a suspension
What is deposition?
When waves drop and leave behind the ‘load’ they were transporting when the water loses energy