mass movement

Spot the difference!

Lesson Objectives

This lesson we will be looking at types of mass movement and weathering.

By the end of this lesson you will be able to:• Name 3 types of weathering and two types

of mass movement• Describe how weathering causes mass

movement• Explain slumping

Weathering and ErosionWeathering and Erosion

Weathering – the breaking down of rock without any involvement of moving forces

Erosion – the breaking down of rock by a moving force such as a wave

Clay

Erosion by waves

Saturation by rainfall (ground cannot hold anymore water

Rotational Slumping

Mass MovementMass Movement• Bottom of the cliff eroded by waves and undercut

• Rainfall saturates cliff and makes it heavier

• Water trapped between layers of rock in the cliff acts like a lubricant

• Rocks slide down cliff in a rotational manner

• Often happens in clay

• Rocks are weathered on the cliff face

• They break loose and fall under the influence of gravity

Coastal WeatheringCoastal WeatheringSalt Crystal Growth Acid Rain Biological

Sea water contains salt.

When water lands on rocks, the water

evaporates leaving salt.

As this process repeats the crystals grow putting

pressure on the rocks causing it to break down into smaller fragments

All rain is slightly acidic.

Polluted air can be very acidic

When rain falls on rocks, the acid reacts with some

of the minerals causing them to dissolve

The roots of vegetation grow into cracks in the

rock.

This splits the rock apart.