Features of coastal erosion/deposition Flashcards
Headland + Bay (erosion)
-A feature of coastal erosion are headlands and bays.
-A bay is a wide, curved opening into the coast.
An example of a bay is Dublin bay.
-A headland is a neck of high land that huts out into the sea.
An example of a headland is the Mizen Head.
- The soft rock (eg shale) is eroded quickly and a bay is formed.
- The hard rock (eg sandstone) is eroded much slower and stands out as a headland.
cliff (erosion)
- A feature of coastal erosion is a cliff.
- An example of cliffs are the cliffs of Moher.
- Waves crash against the coast which is made of hard rock and soft rock.
- The soft rock is eroded faster than the hard rock by hydraulic action (force of the waves) and abrasion (rocks scratching the surface)
- A notch is cut out in the soft rock.
- This notch gets bigger to form an overhang.
- Over time the overhang becomes unstable and collapses.
- Some of the large rocks are dragged out to sea scratching the bed making a wave cut platform.
- The process repeats itself
Sea cave (erosion)
A tunnel found in a cliff formed by hydraulic action, abrasion, etc.
Sea arch (erosion)
Formed when the sea cave cuts through the other side.
Sea stack (erosion)
Formed when sea arch collapses.
Sea stump (erosion)
Formed when sea stack is eroded.
Blowhole (erosion)
Passage that links the roof of a cave with the surface of the cliff top.
Longshore drift (deposition)
Longshore drift is angular/zig zag movement of material along the shore.
The direction that the material moves is affected by the prevailing winds.
Sand spit (deposition)
- A ridge of sand or shingle that is connected to the land at the end and extends into a bay or estuary. eg sutton in dublin
- It is formed when large amounts of material are moved along the coast by longshore drift.
- As it loses energy it deposits material on the sea bed.
- The deposits buiod up to rise above the level of the water.f
Tombolo (deposition)
A ridge of sand and shingle (sand spit) that extends from the land (coast) to an island. eg. Howth in Co. Dublin,
Lagoon (deposition)
Formed when a sand spit (sand bar) extends from one headland across a bay to another headland and blocks a body of water.
Beaches
- A beach consists of sand a shingle.
- Fine material is found at the lower part of the beach.
- Coarse material is deposited at the upper beach.
- In stormy weather the swash is strong enough ti hurl large stones and rocks up past the normal high tide mark where they remain to form a storm beach.
- Finer material is found at the lower part of the beach each due to erosion (eg attrition)
-Sandy beaches can be seen at curracloe in co. wesford,
storm beaches can be seen at garretstown co. cork