Coastal processes Flashcards
Describe the process of Longshore Drift
Prevailing wind direction causes the waves to approach the coast at an angle.
This causes the sediment to be moved along the beach in a zig-zag pattern rather than up an down
What is hydraulic action in coasts
The force of the water hitting the cliff causes trapped air to be forced into the cracks in the cliff.
This air eventually expands the crack and causes the rock to break apart.
What is Attrition
The force of rocks colliding with each other, causing them to become smaller and more rounded
What is abrasion
The force of the rocks in the water colliding with the cliff, causing material to be dislodged and carried away.
What is solution?
When alkaline rocks (e.g limestone) are dissolved by the slightly acidic water
Name the coastal erosion processes
Hydraulic action
Abrasion
Attrition
Solution
What is suspension
When sediment is held up in the sea water
What is saltation
The ‘bouncing’ of rocks that are too heavy to be suspended
What is traction
The rolling of large rocks along the sea bed
Name the coastal transportation processes
Solution
Suspension
Saltation
Traction
What are the four characteristics of constructive waves?
- Formed by storms hundreds of kilometres away
2.Low waves and wave crests far apart
3.Strong swash which deposits sediment onto the beach and weak backwash
4.Common in summer
How are constructive waves formed?
They are formed by storms hundreds of kilometres away
Do constructive waves have a strong or weak backwash?
Weak backwash
Do constructive waves have a strong or weak swash?
Strong swash which deposits sediment onto the beach
What time in the year are constructive waves usually formed?
Summer
Describe the height and wave crests of a constructive wave
Low waves with wave crests far apart
Name the four characteristics of a destructive wave
- Formed by local stroms
- Steep waves with wave crests close together
- Strong backwash which erodes sediment which has been deposited on the beach, weak swash
- Common in winter
How are destructive waves formed?
Formed by local storms
Describe the height and wave crests of destructive waves
Steep waves
Wave crests close together
What time in the year are destructive waves more common
More common in winter
Do destructive waves have a strong or weak backwash?
Strong backwash
Do destructive waves have a strong or weak swash?
Weak swash
Name the three types of weathering
- Mechanical
- Chemical
- Biological
Name an example of mechanical weathering
Freeze-thaw
Describe the process of freeze-thaw weathering
- Water seeps into cracks in the cliff
- At night the temperature decreases and the water freezes and expands, the ice causes the cracks to become wider and deeper
- In the day time the temperature increases, the water thaws and then it seeps further down into the cracks
- The continuous freezing and thawing causes rock fragments to become dislodged and break off collecting as scree at the cliff foot
Name an example of chemical weathering
Carbination (acid rain)
Describe the process of carbonation
ACID RAIN
- Rain water absorbs CO2 and becomes acid rain
- When the acid rain comes into contact with alkaline rocks e.g. limestone, this causes the rocks to dissolve
Describe biological weathering
- Plant (flora) roots grow in cracks in the rock
- Animals (fauna) like rabbits burrow into weak rocks
[blank] describes the natural process which breaks down rocks
fill in the blank
Weathering describes the natural process which breaks down rocks
Name the four types of mass movement
- Rotational SLIP
- Land SLIDE
- RockFALL
- MudFLOW
slip n slide, fall n flow
