Coast Flashcards
(22 cards)
What are the three main coastal processes?
Erosion, transportation, and deposition
What is the definition of Hydraulic action?
This is the erosive power of the water, which removes rock and sand through the constant impact.
What is the definition of Compressed air?
Air becomes trapped in rock cracks by waves. When the waves retreat, the air expands, causing the rock to shatter.
What is the definition of Abrasion?
Pebbles, stones, and rocks are carried by waves and hit against the coastline, breaking off pieces of rock.
What is the definition of Attrition?
Rocks and stones collide with each other as they are carried by waves, becoming smaller and smoother over time until they break into sand.
What is the definition of Solution?
Sea water, which contains salt, slowly dissolves certain types of rocks on the coast.
What is hydraulic action in coastal erosion?
Water pressure removing rock and sand
What is longshore drift?
Waves approach the shore at an angle, moving sediment along the coast in a zig-zag pattern.
The swash (waves moving up the shore) pushes material up at an angle.
The backwash (water flowing back down) pulls material back at a right angle.
This repeated movement causes sand and pebbles to gradually move along the coastline.
What process moves sediment along the coast?
Longshore drift
What is Coastal Deposition?
Deposition occurs when the sea loses energy and drops the sediment it is carrying:
Deposition happens in areas where waves slow down, such as shallow water or sheltered bays.
In summer, waves are weaker, so more material is deposited.
What causes coastal deposition to occur?
Waves slow down
What is the definition of Notch Formation?
Coastal erosion often begins with the formation of a notch at the base of a cliff. Hydraulic action, where the force of the waves hits the rock, creates this indentation. Abrasion, as waves hurl pebbles and sand against the cliff, further deepens the notch.
What is the definition of Sea Cave?
As erosion continues, the notch expands and eventually becomes a sea cave. Hydraulic action and abrasion are key here, gradually hollowing out the rock.
What is the definition of Sea Arch?
When a sea cave continues to be eroded and the waves cut through to the other side of a headland, a sea arch is formed. Compressed air and hydraulic action are particularly important in forcing the rock to give way, creating this open structure.
What is the definition of Sea Stack?
Over time, the roof of the sea arch may become too weak to support itself and collapses. This leaves behind a pillar of rock called a sea stack, isolated from the headland. Attrition further breaks down the collapsed material, leaving the stack standing.
What is the definition of sea stump?
Continuous erosion at the base of the sea stack by processes like hydraulic action and abrasion eventually causes it to weaken and collapse, forming a sea stump. This is the final stage in the erosion of a headland feature.
What is an example of Features of Coastal Erosion?
An example of these features can be seen at Hook Head, Co. Wexford, where sea caves, arches, stacks, and stumps are all present.
What is a Feature of Coastal Deposition: Spits and Tombolos
Coastal deposition occurs when the sea loses energy and drops the material it has been carrying. This process creates various landforms, including sand spits, bars, and tombolos.
Which feature is formed when a sea arch collapses?
Sea stack
What are sand spits?
A sand spit is a long, narrow ridge of sand or shingle that extends from the mainland out into the sea, often across a bay.
What creates a sand spit?
Longshore drift
What creates a sand spit?
Longshore drift
