Erosional Landforms

Question 1

What are the different erosional landforms?

Answer 1

• cliffs
• wave-cut notch + platform
• caves
• arches
• stacks + stumps

Question 2

How is a cliff formed?

Answer 2

• formed as a result of weathering + erosional processes in coastal envi.s

Question 3

How is a steep cliff formed?

Answer 3

• common where rock is strong + fairly resistant to erosion
• sedimentary rocks w vertical strata are more resistant, creating steep cliffs
• absence of beach, long-fetch + high energy waves promote steep cliff dev.
• most common in high energy envi

Question 4

How is a gentle cliff formed?

Answer 4

• common in areas w weaker rocks which are less resistant to erosion + prone to slumping
• low energy waves + shirt fetch forms scree at base of cliff, reducing overall cliff angle
• large beach reduces wave energy, preventing dev. of steep cliffs by dec. erosion rates
• most common in low-energy envi.s

Question 5

What is the rate of retreat of a cliff dependent on?

Answer 5

• marine factors (fetch, beach, wave energy)
• terrestrial factors (subaerial processes, geology, rock strength)
• cliff more likely to retreat if made from unconsolidated rock + sands

Question 6

How is a wave cut notch + platform formed?

Answer 6

• waves erode cliff, mostly concentrated around high-tide line, by main processes of hydraulic action + corrasion to create wave-cut notch
• as notch becomes deeper, cliff faces becomes unstable + falls under its own weight through mass movement, leaving behind a platform of the unaffected cliff base
• over time, process repeats to form a wave-cut platform, which is normally exposed at high-tide

Question 7

How are caves, arches, stacks + stumps formed?

Answer 7

• waves enter faults + cracks in headland, + erode cracks through hydraulic action + abrasion
• cave widens due to marine erosion + sub-aerial processes, eroding through to other side of headland, creating an arch
• arch continues to widen until it falls under its own weight through mass movement, leaving a stack as 1 side of arch becomes detached from mainland
• as marine erosion continues to concentrate at base of stack, eventually it collapses into a stump