Coasts Flashcards
Explain the coastal erosional processes.
C - Corrasion
A - Attrition
S - Solution
H - Hydraulic Action
CORRASION is when waves throw rocks and sand against the coastline, wearing it away like sandpaper
ATTRITION is when the rocks carried by the waves hit each-other, this causes the load to be broken down to smaller and more rounded pieces
SOLUTION this is when the sea water chemically dissolves rocks
HYDRAULIC ACTION is when waves hit coasts and traps compressed air between cracks in the rock, when the wave retreats the air expands with explosive force, creates a ‘mini explosion’ that causes rock erosion
How are headlands and bays formed?
Alternating bands of hard and soft rocks, the soft rock erodes faster through the erosional processes (this is called differential erosion). Indents or bays are formed on the coasts where the soft rock has eroded. This leaves the hard rock that hasn’t eroded as quickly to form headlands
What are wave cut platforms?
This is when waves carve out “wave- cut notches” into the base of a cliff using (explain 2 erosional processes) these notches get deeper and deeper over time.
Eventually the rock above gives out as there’s no support left below, the sea carries the debris away which enhances erosive power.
This process repeats non-stop and slowly the cliff retreats leaving a WAVE-CUT PLATFORM.
Name and explain features that are formed when headlands are eroded.
Cave
Arch
Stack
Stump
CAVE
This begins with a weakness on the side of a headland (a crack), this is eroded (CASH) into a cave.
ARCH
The back wall of the cave is eventually eroded until it breaks through to the other side of the headland to form an arch.
STACK
The base of the arch is then widened until it can’t support itself and collapses into the sea leaving a stack.
STUMP
The base of the stack is eventually eroded until it collapses leaving a stump where the stack once stood.
What is swash and backwash?
SWASH
When a wave reaches a shore the water that rushes up the shore is called swash
BACKWASH
The water that flows back into the sea is called backwash
What is longshore drift?
Longshore drift is the movement of sand and pebbles along a coastline. It is driven by waves and the prevailing winds. It occurs when waves hit the shore at an angle. It is a process that repeats over and over again.
What is a sand spit, bar, and tombola?
SAND SPIT
This is when the materials carried by the longshore drift build up above sea level and leave a long thin section of beach extending out into the sea
BAR
If the sand spit continues to grow and connects to the opposite side of a bay a sand bar is formed
TOMBOLA
If the spit continues to grow and connects a coastline to an island a tombola is formed.
