9 Coastal processes Flashcards
(17 cards)
The coast
Where the land meets the sea, it is the interface between the water and the land
Coastal erosion
Waves wearing away the rock along the coastline and removing the coastal sediments
Erosional processes
- Hydraulic action
- Attrition
- Abrasion
- Solution
Types of Mechanical weathering
- Freeze-thaw weathering
- Chemical weathering
Freeze-thaw weathering
- Water enters cracks, freezes and expands cracks
- Cracks deepen, more water enters and freezes
- Repeated freeze and thaw breaks up rock along the joint lines
Chemical weathering
Caused by a chemical reaction, when rainwater hits rock and decomposes
Discordant coastline
Bands of rock lie at right angles to the coast
Concordant coastline
Band of 1 type of rock runs parallel to the coast
Hydraulic action
Water is forced into the rock, squashing the air inside. Air blasts out when wave retreats. This can break the rock apart.
Atttrition
Loose sediment carried by the sea knock into each other. Break down become smaller and rounded
Abrasion
Rock is picked up and hurled at the cliff by the sea, they scrape and gouge the rock
Solution
Salts in the water can dissolve rocks
Fetch
The distance the wind pushes over the water
How can wind affect the wave?
It affects the fetch, time & wind speed
Swash is the water…
That rushes up to the beach
Backwash is the water…
That flows back towards the sea (at 90 degrees)
Stages of a swash
- Circular orbit in water
- Friction with the seabed disorts the circular orbital motion
- Top of wave moves faster
- Wave begins to break
