Learning Intention: Students will investigate how fossils are formed and understand how the fossil record can be used to make inferences about changing environmental conditions on earth.
Success Criteria: Students will be able to describe how fossils are formed are how they are used to provide evidence for changes on earth over time.
We have learnt about the rock cycle and how different types of rocks are formed. We have also learnt about the different ways that geologists test and identify rocks. Although much of our geology in the western district is dominated by volcanic (igneous) rocks, there is also examples of sedimentary rock formations. Think about the layers of sandstone at Tower Hill (on the right as you drive down into the crater) and the Grampians Sandstone quarry at Dunkeld, where building blocks are cut. Next week we will learn more about how fossils are formed and how we can use fossils to learn about the changes on earth over millions of years.
There are even some local examples of fossils! At Spring Creek, in Minhamite, paleontologists have discovered fossils of ancient megafauna and cetaceans (marine mammals like dolphins). Recently, near the Cape Otway Lighthouse, a vertebrae from the first Australian spinosaur was found. The Warrnambool Standard reported on the finding this week; “When Spinosaurs walked the South West”. The following article, from the ABC “Walking with Dinosaurs” site explains why Australia has very few dinosaur fossils compared to other parts of the world.
“In the dinosaur stakes, Australia was dealt a poor hand for a number of reasons. Firstly, when dinosaurs were roamed the earth, there were few places where the right kinds of rocks were being deposited. Dinosaurs tend to be preserved in sediments laid down by rivers and lakes. During the reign of the dinosaurs most of Australia was covered by a shallow sea.
Secondly, since the age of dinosaurs, there has not been much mountain-building in Australia. If land is lifted up and eroded back, it’s possible to see into the rock beds and find the fossils inside. This has happened in a number of the worlds famous dinosaur deposits elsewhere in the world but not here in Australia.
Lastly, compared to many other places in the world, Australia has very few palaeontologists looking for fossils and a very large area to cover. This is slowly changing and the recent increase in dinosaur fossil finds is a result of more palaeontologists getting out and digging around.”