The role of climate, marine and sub-aerial processes in coastal erosion | Geography

Starter quiz

Which answer correctly describes the difference between climate change and global warming?

Global warming is temperature rise; climate change refers to changes in weather. ✓

Climate change only refers to warming; global warming is changes to weather.

Global warming is caused by nature; climate change is human-made only.

Climate change is short-term; global warming is about daily weather.

Global warming affects the air; climate change affects oceans only.
Features found along discordant coastlines include ______ and headlands.

'bays' ✓
Match the rock types to their correct characteristics.

igneous

⇔

Formed from cooled and solidified magma or lava. ✓

sedimentary

⇔

Made from compacted layers of sediment over time. ✓

metamorphic

⇔

Changed by heat and pressure from existing rocks. ✓

unconsolidated material

⇔

Loose sediments like glacial till not yet cemented into rock. ✓
Re-order the statements to explain the formation of a stump.

1

⇔

Waves find a weakness in the headland and erode the rock over time.

2

⇔

Erosion forms a cave where softer rock is worn away inside the headland.

3

⇔

Continued erosion enlarges the cave until it breaks through the headland.

4

⇔

This creates an arch, which is supported by the harder rock above.

5

⇔

Eventually, the arch collapses due to erosion, leaving a stack behind.

6

⇔

The stack is a tall column of rock standing isolated from the headland.

7

⇔

Over time, the stack erodes further, becoming a stump near the coast.
Identify the correct definition for swash and backwash.

Swash: Cliff erosion; Backwash: Sand deposition onto the beach.

Swash: Water parallel to shore; Backwash: Waves hitting the shore.

Swash: Water up the beach; Backwash: Water returning to the sea. ✓

Swash: High tide forms waves; Backwash: Low tide pulls water away.

Swash: Gentle waves; Backwash: Strong currents back to the sea.
What process does 'the wearing away of rocks along the coastline' describe?

Weathering

Mass movement

Transportation

Erosion ✓

Exit quiz

What type of weathering is caused by plants and animals?

'biological weathering' ✓
What erosion process does the statement 'rocks and sediment collide and break into smaller and smoother pieces' describe?

Hydraulic action

Abrasion

Solution

Attrition ✓
Match up the type of mass movement with its correct definition.

Slumping

⇔

Soil and rock move down in a curved motion. ✓

Landslides

⇔

Sudden drop of loose materials down a slope. ✓

Rockfall

⇔

Rocks and boulders become detached from steep slopes or cliffs. ✓
What factors will determine the strength of a wave?

Wind speed and duration. ✓

The distance wind travels over water (fetch). ✓

Water temperature.

The geology of the coastline.

Worksheet

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Lesson Details

Key learning points

Climate (seasonality, storm frequency, prevailing winds) affects the rate of erosion along coastal landscapes.
Marine processes (destructive waves) affect coastal landscapes and the rate of coastal retreat.
Sub-aerial processes (mass movement, weathering) affect coastal landscapes and the rate of coastal retreat.

Common misconception

Swash is when a wave moves down the beach to the sea and backwash is when a wave moves up the beach from the sea.

The swash is the movement of the wave from the sea to the beach which brings sediment with it. Whereas the backwash is the movement of the wave from the beach to sea.

Keywords

Erosion - the wearing away of rocks along the coastline
Constructive wave - low-energy waves that result in the buildup of sediment along the coastline
Destructive wave - high-energy waves that result in the removal of sediment along the coastline
Weathering - the breaking down or dissolving of rocks through plants, animals and weather
Mass movement - downhill movement of sediment due to gravity