Marine Erosion

Question 1

What is erosion?

Answer 1

• the removal of sediment from a coastline

Question 2

What are the main processes of erosion?

Answer 2

• hydraulic action
• corrasion
• abrasion
• solution
• attrition

Question 3

What is hydraulic action [1] + cavitation [2]?

Answer 3

[1]
- when waves crash onto a rock or cliff face, air is forced into cracks, joints + faults within the rock
- as wave retreats, the air expands + the high pressure causes cracks to force apart + widen causing rock to fracture over time

[2]
- bubbles in water implode under high pressure + eject tiny jets of water that erodes rock over time

Question 4

What is corrasion?

Answer 4

• when sand + pebbles are picked up by sea, from an offshore sediment sink or temporal store, + hurled against the cliff at high tide, causing cliffs to be eroded

Question 5

What affects the erosive power of corrasion?

Answer 5

• shape, size, weight + quantity of sediment picked up
• wavespeed

Question 6

What is abrasion?

Answer 6

• when sediment is moved along shoreline, in a sandpaper motion, causing it to wear down over time

Question 7

What is solution?

Answer 7

• when water dissolved rocks + minerals into solutions
• similar to carbonation weathering as mildly acidic water can cause alkaline rock to be eroded

Question 8

What is attrition?

Answer 8

• when wave action causes rocks + pebbles to hit against each other, wearing each other down + so becoming rounder + smaller