Coastal Landforms

Question 1

Examples of Erosional Coastal Landforms

Answer 1

• Wave-Cut Platforms
• headlands
• Bays
• Caves
• Arches
• Stacks
• Stumps
• Cliffs

Question 2

Wave-Cut Platform Formation

Answer 2

• Waves hit the cliff around the high-tide line, hydraulic action occurs as air is forced into pockets. in the rock and pressurised, breaking and widening fractures in the rock, causing expansion and destabilising the rock face
• Erosionary forces such as attrition, solution and abrasion expand the fracture causing a wave-cut notch
• This wave-cut notch makes the cliff above it unstable, and as it widens, the cliff face may collapse
• The wave-cut platform is formed and the cliff face retreats. The process starts again

Question 3

Processes affecting the development of a Wave-cut Platform

Answer 3

• Hydraulic Action
• Abrasion
• Chemical Weathering
• Sub-aerial Weathering
• Mass Movement

Question 4

Factors affecting the development of a Wave-cut Platform

Answer 4

• Dip of Cliff Face
• Angle of Bedding Planes
• Natural Weaknesses
• Joints Present
• Fetch
• Windspeed
• Depth of Water
• Energy of Waves

Question 5

Cracks, Caves, Arches, Stacks and Stumps Formation

Answer 5

• Initially, faults in the headland are eroded by hydraulic action and abrasion to create small caves
• Eventually, the cave is eroded so deep into the rock that it reaches the other side of the rock and an arch is formed
• Weathering and Erosion makes the roof of the arch unstable and it collapses, leaving an isolated column of rock, a stack
• Weathering weakens the top and wave action weakens the bottom until the stacks becomes a stump

Question 6

Processes and Factors affecting the Development of the Crack, Cave, Arch, Stack, Stump Succession

Answer 6

• Joint/Fault Presence
• Type of rock affects type of weathering occurring
• Hydraulic Action, Abrasion, Attrition, Solution all wear away the rock
• Wave Energy due to fetch, windspeed, water depth

Question 7

Formation of Blowhole

Answer 7

A crack occurs in the cliff due to a joint/fault. This is eventually widened by erosional forces into a sea cave
- This cave is then enlarged into the cliff face, if this occurs beneath a vertical joint, then it destabilises the face
- The pressure forces the vertical crack to collapse and the air pushes through, forming a blowhole

Question 8

Processes and Factors affecting the Formation of a Blowhole

Answer 8

• Marine Erosion, such as hydraulic action, abrasion, attrition, solution
• Physical and Chemical Weathering
• Presence of Joints and faults in the rock
• Air + Water pressure to force open a shaft