Theme 2 People and the Natural World Key idea 4

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Transcript Theme 2 People and the Natural World Key idea 4

WJEC (B) GCSE Geography

Theme 2 Topic 6

Coastal erosion

Hodder Education

Revision Lessons

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WJEC (B) GCSE Geography

Theme 2 Topic 6

Coastal erosion

How does a headland erode?

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WJEC (B) GCSE Geography

Theme 2 Topic 6

Coastal erosion

Headlands form along coastlines in which bands of soft and hard rock outcrop at right angles to the coastline. Less resistant rock (e.g. boulder clay) erodes more rapidly than less resistant rock (e.g. chalk).

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WJEC (B) GCSE Geography

Theme 2 Topic 6

Coastal erosion

The following slides show the sequence that takes place when a headland is attacked by wave action.

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WJEC (B) GCSE Geography

Theme 2 Topic 6 1 Wave-cut notch

Waves erode the base of the cliff by hydraulic action and abrasion. In the case of this chalk cliff at √Čtretat in Normandy, the chalk rock is also dissolved by corrosion.

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WJEC (B) GCSE Geography

Theme 2 Topic 6 2 Cave

Lines or zones of weakness along the cliff erode more quickly than the rest of the headland and form caves. Such wearing away at different rates is known as differential erosion.

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WJEC (B) GCSE Geography

Theme 2 Topic 6 3 Arch

Over a long period of time, the cave erodes deeper into the headland. Another cave forms on the other side of the headland along the same line of weakness. Gravity causes loose rock to fall from the roof of the cave. The two caves finally join to form an arch.

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WJEC (B) GCSE Geography

Theme 2 Topic 6 4 Stack

Agents of erosion continue to work on the rock forming the arch. Eventually, the roof collapses due to gravity, forming a stack. Weathering of the rock also takes place. This stack erodes and weathers further to form a low-lying stump before eventually eroding to sea level.

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WJEC (B) GCSE Geography

Theme 2 Topic 6 5 Wave-cut platform

As the cliff slowly retreats, a gently sloping area of rock is left behind at sea level. This is a wave-cut platform.