coastal landforms

Answer: Waves erode the base of the cliff through hydraulic power and abrasion, creating a wave-cut notch (1 mark). The notch undercuts the cliff above, making it unstable (1 mark). The overhanging cliff collapses through mass movement, and the debris is washed away (1 mark). As the cliff retreats inland, a flat rocky platform is left exposed at low tide, marking the former position of the cliff (1 mark).

Answer: Waves erode the base of the cliff through hydraulic power and abrasion, creating a wave-cut notch (1 mark). The notch undercuts the cliff above, making it unstable (1 mark). The overhanging cliff collapses through mass movement, and the debris is washed away (1 mark). As the cliff retreats inland, a flat rocky platform is left exposed at low tide, marking the former position of the cliff (1 mark).

Answer: Waves exploit a weakness (crack or joint) in the headland through hydraulic power, enlarging it into a cave (1 mark). The cave is eroded right through the headland by wave action, creating an arch of rock above a tunnel (1 mark). Weathering and erosion weaken the roof of the arch until it collapses, leaving an isolated pillar of rock called a stack (1 mark). The stack is further eroded by waves and weathering, reducing it to a small stump visible at low tide (1 mark).

Answer: Spurn Head in Yorkshire is a 5.5 km long spit formed by longshore drift. Prevailing north-easterly waves transport sediment southwards along the Holderness Coast (1 mark). When the coastline changes direction at the Humber Estuary, longshore drift continues to deposit sediment in the same direction, extending the spit out into the estuary (1 mark). The end of the spit curves round (recurved) due to wave refraction changing the direction of wave approach (1 mark). Behind the spit, sheltered water allows fine sediment to accumulate, forming salt marshes (1 mark).

Answer: Erosional landforms are created where wave energy wears back the coastline - headlands form where hard rock resists erosion, while bays form where soft rock retreats (1 mark). Cliffs and wave-cut platforms form through undercutting and cliff collapse (1 mark). Caves, arches and stacks develop on headlands where concentrated wave energy exploits weaknesses (1 mark). Depositional landforms form where wave energy decreases and sediment accumulates - beaches form in sheltered bays from constructive wave deposition (1 mark). Spits extend from the coast where longshore drift deposits sediment across bays or river mouths (1 mark). Bars and tombolos form when spits grow to connect headlands or islands (1 mark). Erosional landforms dominate on exposed, high-energy coastlines, while depositional landforms dominate in sheltered, low-energy areas.

Answer: I agree that geology is very important because rock type determines whether a coastline features erosional or depositional landforms - hard resistant rocks like chalk and limestone form headlands, cliffs, caves and stacks, while soft rocks like clay form bays (1 mark). Discordant coastlines with alternating hard and soft rock produce the classic headland and bay pattern, while concordant coastlines produce more uniform features (1 mark). The geological structure (joints, faults, bedding planes) controls where caves and arches develop (1 mark). However, wave energy is also crucial - high-energy coasts experience more erosion regardless of geology, while low-energy coasts favour deposition (1 mark). Sediment supply is important for depositional landforms - without a supply of material, beaches, spits and bars cannot form (1 mark). The shape of the coastline affects wave refraction, concentrating energy on headlands (1 mark). Human activity can override natural processes through coastal defences that alter sediment transport (1 mark). Climate and sea level change are also significant factors over longer timescales (1 mark). On balance, geology provides the fundamental template, but the interaction of geology with wave energy, sediment supply and coastal shape determines the specific landforms that develop (1 mark).