1. Topic 2 – Lesson 1
Mountain Building

2. Introduction
Mountain ranges provide some of the most spectacular scenery on this planet.

3. Introduction
Because Australia has such an ancient landscape our mountains are small because they have been eroded. For example Mt. Kosciusko is only 2228 metres high.
Mt Everest is 8848 meters high!

4. Mountains and Plate Collisions
When crustal plates collide, the enormous compression forces involved help to create mountains. Because Australia is located in the middle of a plate and the land is so ancient, we will have to look at mountains in other parts of the world.

5. Mountains and Plate Collisions
Activity
Read and discuss pages HSC Spotlight Text.
Complete Activity 1.5,1.6, and Split the class into three groups and have and divide the activities. Give students minutes to complete the tasks. Give each group 5 minutes to present their findings to the class.

6. Homework Complete Activity 1.8 pg 14 HSC Spotlight Text
Complete ‘To Think About’ pg 11 HSC Spotlight Text
Update electronic vocab pg 7-11

7. How Australia has changed
Topic 3 - Lesson 1
How Australia has changed

8. Review
When crustal plates collide, the enormous compression forces involved help to create mountains.
Key Concepts:
Folds
Faults
Antisyncline and syncline
Reverse fault and normal fault
Shear forces
Lateral fault

9. Introduction
The overall history of the Australian continent is relatively easy to determine from the break up of Pangaea at the end of the Permian.

10. Introduction
Evidence of plate movements still exist from this time on the ocean floor however because of subduction, plate movements before the Permian are harder to predict.
Activity:
See timescale on pg 143 HSC DOT Point (will be on exam)

11. Introduction
All we have for evidence before the Permian is preserved in ancient mountain chains found on continents. This evidence suggests that at least twice in Earth’s history the continents joined to form one body and then separated. This process seems to be cyclic and has therefore been named the tectonic supercycle.
This cycle has helped shape geology and climate. Do you think it could have effected biological evolution? Explain

12. Plate Tectonic Supercycle
Scientists have called the first supercontinent Rodinia.
Rodinia broke up late in the Proterozoic 750mya (see timeline in DOT Point Book pg 143)

13. Plate Tectonic Supercycle
The continents spread apart for about 400 million years until they joined once again to form another supercontinent called Pangaea in the early Permian about 280mya.

14. Plate Tectonic Supercycle
Pangaea began to break apart in the late Permian (250 million years ago) to form two large continents called Laurasia and Gondwana.

15. Plate Tectonic Supercycle
Gradually Laurasia and Gondwana separated to form what we see today. What do you think the Earth will look like in another 250 million years?

16. Plate Tectonic Supercycle
Why would such large supercontinents break apart?
When you have such a large supercontinent it acts as a blanket over the mantle and results in heat build up. The continent begins to rise and eventually crack. The upwelling of heat in the mantle forces the broken pieces to move apart.

17. Plate Tectonic Supercycle
This understanding of plate tectonics has changed the science of geology significantly.
Economic geologists use previous positions of crustal plates to locate minerals
Palaeontologists have had to rethink the aspects of evolution
Mechanisms now exist to provide explanations of geological structures and landforms
Oceanographers are using plate tectonics to better understand the ocean currents

18. Plate Tectonic Supercycle
Activity
Complete Activity 1.9 and 1.10 pg 18 HSC Spotlight Text

19. Review
Rodinia was one of 2 supercontinents in Earth’s history. This broke up late in the Proterozoic ( myo)
Pangaea formed early in the Permian (300myo) and began to sepatate late in the Permian (250myo)
As Pangaea separated it formed 2 large continents: Laurasia and Gondwana.
The process of continents joining and separating seems to be cyclic and is called the tectonic supercycle.

20. Homework Read page 17 HSC Spotlight Text Update electronic vocabulary
Complete DOT Points

21. How Australia has changed
Topic 3 - Lesson 2
How Australia has changed

22. Review
Rodinia was one of 2 supercontinents in Earth’s history. This broke up late in the Proterozoic ( myo)
Pangaea formed early in the Permian (300myo) and began to sepatate late in the Permian (250myo)
As Pangaea separated it formed 2 large continents: Laurasia and Gondwana.
The process of continents joining and separating seems to be cyclic and is called the tectonic supercycle.

23. Growth of Australia
As we read in the text book, Australia passed over and old subduction zone which resulted in the continent lowering under water and then rising again. Australia has changed over time and formed in regions of the Earth far from where we are today.
Look at diagrams 1.17 and 17 on page 12 HSC Spotlight Text

24. Growth of Australia
Like Australia, the other continents have also changed over time. Each however has the same basic structure:
Large stable areas of Precambrian rocks
Belts of folded rocks showing intense deformation
Broad areas of relatively undisturbed sedimentary rocks called continental basins lying on top of the stable Precambrian areas and belts of folded rocks
See Figure 1.18 pg 19 HSC Spotlight Text

25. Growth of Australia
Somewhere in each continent are large stable areas of complex Precambrian rocks known as cratons. These rocks underwent intense periods of deformation in Precambrian times and are made of granite and metamorphic rocks.

26. Growth of Australia
If cratons are exposed at the surface they are called shields. They may be covered by a thin layer of sedimentary rock called platforms. In Australia the major cratons are in the western part of the country.

27. Growth of Australia
The eastern part of Australia is a region of fold belts. This is evidence that at one time they were along the edge of a crustal plate! Now though, they are stable.

28. Growth of Australia
Between the end of the Proterozoic and the breakup of Gondwana in the late Permian, there was a subduction zone along the eastern edge of Australia. For about 300 million years the Australian Continent grew towards the east.

29. Growth of Australia
If you look at Figure on page 20, you can see evidence of volcanic island arcs off the coast of the craton. Between the island arc and the craton was a shallow inland sea.
Discuss this diagram in detail
See Video

30. Growth of Australia
Between the subduction zone and the island arc is pile dup sediments scraped from the oceanic crust. As the ocaenic crust is forced into the mantle is takes water and ocean sediments with it. This lowers the melting point of rocks and magma begins to rise to the surface creating the volcanic islands.

31. Growth of Australia
A lot of the re-melted rocks which have turned into magma do not make it to the surface and cools under ground to form giant batholiths. The combined effects of volcanism and metamorphism result in stable mountains in the island arc.

32. Growth of Australia
As the island arcs move eastward they leave behind folded but stable rocks we can see today. Currently the subduction zone has moved hundreds of kilometres to it’s current location running from Tonga to New Zealand.

33. Growth of Australia
Large areas of sediments cover the shields and fold belts. The most famous is the Great Artesian Basin which formed during the Jurassic and Cretaceous. Further East lies the Sydney Basin. See diagrams on pages HSC Spotlight Text to help explain this.

34. Review
The eastern part of Australia is a region of fold belts. This is evidence that at one time they were along the edge of a crustal plate.
Between the end of the Proterozoic and the breakup of Gondwana in the late Permian, there was a subduction zone along the eastern edge of Australia. For about 300 million years the Australian Continent grew towards the east.
Currently the subduction zone has moved hundreds of kilometres to it’s current location running from Tonga to New Zealand.

35. Homework Read pages 19-20 HSC Spotlight Text
Update electronic vocabulary
Complete DOT Point 3.1
Complete To Think About pg HSC Spotlight Text