55 million years ago - ghosts of Gondwana
About Murgon
Murgon is located in south-east Queensland. Around 55 million years ago it was a swampy lake with a diversity of vertebrate animals living in the area, 10 million years after the mass extinction at the end of Cretaceous Period. At this time mammals were diversifying, after living in the shadow of the dinosaurs for millions of years. Murgon fossils provide evidence that at this time Australia was still joined to South America and Antarctica as part of the supercontinent Gondwana.
Significant fossils from Murgon
One of the most internationally important finds from Murgon is a tiny tooth of a placental mammal, Tingamarra porterorum, probably the oldest placental mammal found in Australia. Before this find scientists thought that non-flying mammals hadn't colonised Australia until around 5 million years ago. With this discovery came the realisation that both placental and marsupial mammals were in Australia 55 million years ago.
Murgon is the site where some world record fossils have been found. These include the earliest songbird fossil found in the world, one of the world's oldest bats and the only known fossils of leiopelmatid frogs. Other finds include Australia's oldest marsupial, frog and crocodile fossils as well as the only fossils of salamanders found in Australia.
Palaeontologists excavating at a fossil quarry at Murgon. Brushes and fine tools are used to remove clay from around fossil bones such as this crocodile skull (right).
Photos: © H Godthelp.
Fossil-hunting at Murgon
Palaeontologists looking for fossils at Murgon must first remove tonnes of overlying soil to expose the rich, fossil-bearing green clay which is carefully excavated. Any large fossils, such as bones and turtle shells are wrapped in plaster for transport. The rest of the clay is put in bags and all is transported back to the lab at the University of New South Wales. Here the clay is dried in ovens and then washed through fine sieves that trap the tiny fossil bones and teeth.
