Coastal Erosional Landforms and Weathering Flashcards
coastal morphology
shape of coastline
cliff profile
characteristics and appearance of a cliff face
describe how wave-cut platforms are created
- as waves break at the foot of the cliff, a wave cut notch is created, which undercuts the cliff
- this is due to erosional processes such as hydraulic action and abrasion
- this becomes unstable and collapses as abrasion erodes the cliff
- the notch moves inland creating a shoreline platform
- the cliff will collapse, causing the cliff to receed and retreat backwards due to instability as the weight was too much. temporary rock armour forms at the base of the cliff.
briefly describe shoreline platforms
has a gentle slope, normally exposed at low tide
-absorb energy- act as a beach as they cause the waves to break earlier.
give an example of a shoreline platform
Southerndown Glamorgan in South Wales
give an example of a wave-cut platform
Flamborough Head in Yorkshire
describe how caves, arches, stacks and stumps are created
- joints, faults or vertically dipping bedding planes create weaknesses in the rock
- hydraulic action deepens and widens the weak points, forming a sea cave
- marine erosion deepens the sea cave, until a tunnel forms in the headland, forming an arch
- the undercutting leads to material collapsing- mass movement. additionally, weathering and sub-aerial processes attack the arch roof.
- it collapses and leaves a tall vertical column called a stack
- marine erosion at the base will cause a blockfall, a stump which is only exposed at low tide
give an example of a stack and stump
Old Harry’s Rocks, Handfast Point, isle of Purbeck in Dorset
(three chalk formations)
cliffs
-steep vertical rock faces at the edge of the sea
-chalk cliffs can lead to the formation of caves, arches, stacks and stumps
give an example of a cliff (reteating)
The White Cliffs of Dover
(chalk cliffs)
example of coastal retreat
describe how headlands and bays are formed
- they only form on discordant coastlines where there are alternate geology bands of hard and soft rock
- soft rock is more susceptible to erosion, so it erodes at a faster rate
- bays form where the waves erode soft rocks , but headlands are left as land that juts out into the water.
give an example of a headland and bay
Swanage Bay, Dorset
- the clay here erodes at a faster rate than the limestone and chalk
-between the two headlands Ballard Point an Durlston Head
what type of coastline do headland and bays form on? and why?
discordant coastline- differential erosion takes place
give 4 types of erosion
hydraulic action
abrasion (corrasion)
solution (corrosion)
attrition
describe hydraulic action
as water crashes into small cracks in the cliff, air gets trapped, it is compressed and expands, weakening the rock, leading to it breaking
describe abrasion/ corrasion
as the sea crashes into the cliff the rocks are hurled up against the cliff, becoming more rounded and smooth
describe solution (corrosion)
small pieces of sediment dissolve in the sea water, the acidic water dissolve minerals in the rock face (can cause a holey face)