Features Of Erosion Flashcards
Example of a headland
Swanage Bay, Purbeck Coast.
Where are headlands and bays formed?
On discordant coastlines where hard and soft rock are both exposed along the coastline. Alternating layers run perpendicular to the water.
What is differential erosion?
Alternating rate of erosion due to different rock types.
Summary of headland and bay formation
Alternating layers, soft rock eroded more quickly, bay is formed. Hard rock left jutting out into the sea, known as headland.
Wave refraction impacts on headland and bays
Wave refraction concentrates erosion on headland and reduces erosion and development of bays due to loss of wave energy. Sub-aerial processes become responsible on furthering development of bay by eroding it (corrosion and corrasion).
What is a wave cut notch?
A small indent at the base of a cliff formed when a cliff is undercut by the sea.
How are wave cut notches formed?
Destructive waves break on a cliff, concentrating energy on one specific point, experiencing more rapid erosion via abrasion. The cliff becomes undercut -> forming a wave cut notch.
How is a wave cut platform formed?
Undercutting of a cliff means that overhanging cliffs become unstable above the notch and so collapse. This process repeats leading to ‘cliff retreat’. A gentle platform is left behind as a consequence of cliff retreat
Erosion of a wave cut platform
Transportation of rock and sediment scarres the platform.
How does a wave cut platform reduce erosion?
As the platform grows, waves have to travel further to cliff and therefore lose their energy. Once the platform reaches a certain size, waves will have to little energy to undercut the cliff, therefore their is a physical limit on size of platform.
Blowhole
Forms in a cave. As caves move inland, roof is weakened. Waves crash into the cave and are reflected upwards eroding the roof, and eventually breaks through with the aid of weathering, forming a blowhole.
Geo
Linear landform as a result of accelerated erosion along a faultline. A geo is a steep sided inlet into the side of the coast, formed at a weakness or faultine.
What makes a cliff particularly susceptible to erosion?
Areas that have small cracks and joints.
Bedding layers in line with the wave direction.
Formation of caves
Weak areas of rock will be eroded very quickly. They are undercut and a small cave will form. If cave forms on headland, a second will develop simultaneously on opposite side of headland.
Formation of arches (from a cave)
Water erodes the cave by corrosion and hydraulic action, widening and flooding out the caves until they meet, resulting in an arch through the headland.
