coastal erosion

Question 1

sea cave

Answer 1

• rocks contain weak points that are more easily eroded
• lines of weaknesses are formed which over time are enlarged due to
• hydraulic action (desc)
• abrasion (desc)
• sometimes a blowhole can form in the roof of the cave
• as compressed air is pushed upwards by the power of the waves, causing vertical erosion

Question 2

arch

Answer 2

• rocks contain weak points that are more easily eroded
• lines of weaknesses are formed which over time are enlarged due to
• hydraulic action (desc)
• abrasion (desc)
• there may be erosion on both sides of the headland due to wave refraction until eventually the sea cuts through the back walls of the caves, forming an arch
• continued erosion enlarges the arch

Question 3

headlands and bays

Answer 3

• Headlands form along discordant coastlines whereby bands of soft rock and hard rock stick out at right angles to the coastline
• Differential erosion occurs where the soft rock (e.g. clay) erodes more quickly than the hard rock (e.g. chalk)
• The soft rock is eroded more rapidly by abrasion (desc), solution and attrition than the hard rock, which forms bays.
• The more resistant rock is eroded at a slower rate by hydraulic action (desc) leaving the hardrock sticking out into the sea as a headland.
• An example is Lulworth Cove in dorset

Question 4

wave cut platform

Answer 4

• Weaknesses such as joints, faults or cracks in cliffs are undercut by erosion to form a wave-cut notch
• Erosion takes place due to hydraulic action (desc)
• Abrasion (desc)
• the rock above the wave-cut notch overhangs and as erosion continues, the notch enlarges until the unsupported overhang collapses due to its own weight and gravity
• the new cliff face is then eroded and over time, the cliff retreats inland leaving a gently sloping rocky surface called a wave-cut platform which extents out to sea away from the cliff