Secondary source investigation 4. 1. 1 Formation of Australia as an island continent from Gondwana Aim: to investigate evidence supporting the inference that the Australian continent is moving. To construct a timeline to identify key events in the separation of Australia from Gondwana. 1. Develop a timeline to identify the key events in the formation of Australia as an island continent (emphasise the development of Australian fauna and flora) : . Identify a plant and an animal fossil that provide evidence that Australia was once part of Gondwana: Nothofagus or Southern Beech. A genus of around 40 extant species of trees. 3. Describe the theory of plate tectonics and identify its role in the formation of Australia as an island continent: The theory of plate tectonics states that Earth’s crust and the outermost part of the mantle are mechanically connected to each other.
This layer is broken into several plates that move about Earth’s surface. As they move about, they are constantly interacting with each other along their boundaries. Its role in the formation of Australia as an island continent is that the great plateau of the Western Australian Shield forms the core of the ancestral continent, which, with Antarctica, split off from Gondwanaland during the Jurassic era, less than 200 million years ago, and began to drift eastwards and northwards.
Australia emerged as a separate continent about 100 million years ago, when Antarctica broke away and drifted southward. 4. Lungfish, the Wollemi pine and Antarctic beeches Nothofagus are living fossils. Discuss their importance as evidence for Australia once being part of Gondwana: These living species have different patterns of distributions, which show the areas that the species exist.
These pattern distributions allow for the understanding of Australia’s inclusion in Gondwana through tracing the certain areas of existence, and comparing them to the giant continents. 5. Explain why Glossopteris is used as evidence for the existence of land bridges: Once Gondwanaland broke up, the remains of this species were found on many different continents, and the rocks that these fossils are found in are all dated at the same age. Therefore the existence of land bridges explains the distribution of this species.
