Flashcards in 3 Coastal Landscapes Deck (10):
Types of erosion (4)
Abrasion, attrition, hydraulic action and solution.
Types of transportation (5)
Longshore drift, solution, saltation, suspension and traction.
Types of mass movement (3)
Slumping, sliding and rockfall.
Types of Weathering (3)
Chemical, biological and mechanical.
Main type of mechanical weathering
- Water gets into the cracks of rocks
- The water freezes which causes it to expand, putting pressure on the rock
- When the water thaws it contracts, releasing the pressure on the rock
- Repeated freezing and thawing widens cracks and causes the rock to break up
What waves carry out erosional processes?
- High frequency (10/14 waves per min)
- High and steep
- Backwash more powerful than swash
Explain the formation of wave-cut platforms
- Waves cause most erosion at the foot of a cliff
- This forms a wave-cut notch which is enlarged as erosion continues
- The rock above the notch becomes unstable and eventually collapses
- The collapsed material is washed away and a new wave-cut notch starts to form
- Repeated collapsing results in the cliff retreating
- A wave-cut platform is the platform that’s left behind as the cliff retreats
Explain the formation of headlands and bays
- Soft rock has low resistance to erosion. Hard rock has a high resistance to erosion.
- Headlands and bags form where there are alternating bands of resistant and less resistant rock along the coast
- The less resistant rock (e.g. clay) is eroded quickly and this forms a bay (bays have a gentle slope)
- The resistant rock (e.g. limestone) is eroded more slowly and is left jutting out, forming a headland (headlands have steep sides)
Explain the formation of caves, arches and stacks.
Headlands are eroded to form caves, arches and stacks.
- Waves crash into the headlands and enlarge any cracks by hydraulic action and abrasion
- Repeated erosion and enlargement of the cracks causes a cave to form
- Continued erosion deepens the cave until it breaks through the headland forming an arch
- Erosion continues to wear away the rock supporting the arch until eventually it collapses, this forms a stack (an isolated rock that’s separate from the headland)