1. South Island High Country
Land modifying processes:
Glaciation
Fluvial erosion
Freeze – Thaw action
Wind Erosion
Mass movement

2. Land Building Processes Land Modifying Processes
Cycle of Landforming
Land Building Processes
Folding
Faulting
Volcanism
Land Modifying Processes
Erosion
Weathering Transportation
Deposition
Causes of erosion
Glaciers Rivers
Wind Freezing and Thawing

3. Weathering
Copy/summarise the definition for weathering from the Geography on the Edge textbook from page 25.
Write 1 sentence to explain expansion and contraction.

4. Different types of erosion in our environment
Fluvial
Caused by the action of rivers/water – Mainly where?
Glacial
Caused by the action glaciers – Mainly where?
Freeze-Thaw
Caused by the freezing and melting of water in rocks. As water freezes and can cause rocks to shatter. Mainly where?
Aeolian
Caused by the movement of wind – Mainly where?

6. Due to high altitudes (and cool temps) Glaciation is an important land-modifying process.
Some glacial features that can be seen throughout the High Country are:
U-shaped valleys – which form as glaciers advance down the valley. e.g.
Deep Finger Lakes - which are in old glacial valleys. e.g.
Cirques – bowl/arm chair shaped basins where glaciers begin. e.g
Horn Peaks – e.g.

7. Arête
Using the information on page 29 draw a quick (5 min) annotated diagram of how an arête forms.
Make sure you give an example from the SAs.

8. Many of these features were formed during ice ages, the last ice age started about 2 million years ago and ended approx. 10,000 YA.
During this time most of the South Island was covered in ice.
The glaciers formed in Cirques (hollows at the heads of valleys) and grew larger and heavier, they then travelled down the valleys, eroding the sides and floors of the valley as they travelled.

9. Helpful diagram to explain present and past glaciation processes
Go to page 28 in Geography on the Edge text and combine the During and After Glaciation diagrams to show what’s happening in our region.
Make it specific to the SA/EHC
HINT – the valley on the left is The Hooker and the valley on the Right is The Tasman
If you want to get the scale more correct use the Topo map from page 7 to help.

10. Medial Lateral Terminal moraine
Often when the glacier retreats the terminal moraine at the former nose of the glacier dams the water and forms a finger lake in the U-shaped valley behind

11. Freeze-thaw
The intense cold of the High Country (esp at night) means the peri-glacial process of freezing and thawing is very active.
Erosion from freeze-thaw occurs when water seeps into a crack in a rock, at night the freezing of this water causes it to expand as it turns to ice – causing the crack to widen. When thawed water seeps further into the crack – freezes – widens – thaws – seeps
This causes rocks to break up, resulting in giant shingle slides which can be 100s of metres high. These are called scree or talus slopes.

12. Copy the freeze-thaw diagram below

13. Now add some specific evidence from the following information to your diagram.
Finally…

14. What particular feature (relief characteristic) does freeze-thaw create?
Can you name/locate one in the Eastern High Country?

15. This can be caused by a number of factors: Steep slopes
Mass movement is the slipping of rock and soil down a slope either as rockfalls or landslides or slips.
This can be caused by a number of factors:
Steep slopes
A weak geological structure
Earthquakes
Prolonged periods of rain – lubricating the soil.
24th Dec 1991
Mount Cook
10m

16. Read bullet point 2 on page 10.
Write one sentence to explain the mass movement process which changed Aoraki in 1991.Include specific evidence. But that’s not all….

17. Aeolian (wind) erosion
Important where there are strong prevailing winds e.g. in the relatively dry Eastern High Country. Fine particles of dust or unconsolidated soil, loosened by rock-slides, sheep etc are blown down slope towards the east. Some parts on the edges of the Eastern High Country and further East (Canterbury Plains) have been covered in fine grit and dust called Loess, which is blown down by the föhn winds (hot, strong, dry northeast wind that blows down from the Southern Alps). This process is not as active as other erosional forces.

18. Copy the diagram below - give it a title and any specific evidence you can.
Fohn Wind blows unconsolidated soil
Zone of wind erosion
Canterbury plains
Zone of loess deposition
South Island High Country

19. Skills break
Use the following slide to create three percentage bar graphs.
Apply appropriate conventions.

20. New Zealand’s Landform Patterns
% Mountains
% Rough Hill Country
% Rolling Hill Country
% Plateau
% Plains
New Zealand 49 25 15 3 8
North Island 18 45 26 6 5
South Island 70 12 9

21. Glaciers/glaciation processes
Cirques

22. Theory of glaciers…. Glaciation full length DOC powerpoint. Watch