2. 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
3. Weathering 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
4. Saturation by rainfall (ground
cannot hold anymore water
Clay
Rotational Slumping
Erosion by waves
5.
6. Mass 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
7. Coastal Weathering
Salt Crystal Growth Acid Rain Biological
Sea water contains salt. All rain is slightly acidic. The roots of vegetation
grow into cracks in the
When water lands on Polluted air can be very
rock.
rocks, the water acidic
evaporates leaving salt. This splits the rock apart.
When rain falls on rocks,
As this process repeats the acid reacts with some
the crystals grow putting of the minerals causing
pressure on the rocks them to dissolve
causing it to break down
into smaller fragments
