Jurassic Gorge
By Dr Susan Parfrey
About 95km south of Rolleston, in the southern part of central Queensland, Australia, is a national park that contains the Carnarvon Gorge. The gorge is over 32km in length and is formed of towering white sandstone cliffs. It has almost everything a visitor could want – beautiful scenery, wonderful Aboriginal rock paintings and a garden of moss with a magic waterfall, plus King Ferns, the largest ferns in the world. So what’s missing? Well, obviously, Jurassic dinosaurs.
This is one of the most popular national parks in the state and has over 30,000 people visiting every year. Over the years, you would imagine every centimetre of rock has been carefully studied and, in particular, the ‘Art Gallery’ Aboriginal rock paintings, some of which date back 3,600 years. Imagine the surprise in 1992 when some tourists told the Park Ranger they thought there were bird footprints in a rock at the Art Gallery. The ranger examined the site and, sure enough, there were some marks on the rock. But were they footprints? The Park Ranger took photographs and sent them to the sloe palaeontologist at the Geological Survey of Queensland in Brisbane.
Throughout my career as a geologist, I have seen every shape possible formed in rocks. Nature has an amazing ability to cut interesting shapes in natural objects. Combine this with people’s imaginations and you can come up with almost anything. So, when the Park Ranger said a tourist had found something that might be footprints in the rocks of the gorge, I had my usual doubts. When the photographs arrived, they did look like dinosaur footprints, but to confirm this, we needed to look at the original material. The ranger removed the slab of rock containing the prints and sent it to Brisbane for further investigation.
The fossil site is about 5km west of the park’s information centre into the gorge at the Art Gallery. The rock in the Art Gallery is formed from the Precipice Sandstone that was deposited in the early Jurassic around 195 to 200 million years ago. Seven full or partial footprints of a small dinosaur were preserved in the sandstone. A local expert, Tony Thulborn, examined the rock and confirmed the footprints belonged to an ornithopod dinosaur similar to an ichnospecies (the name given to a trace fossil that is left behind by biological activity such as a footprint) called Anomoepus gracillimus.
The footprints, which range in length from 6.4 to 7.2cm, suggest the prints belong to several dinosaurs which were no longer than 1.3m. The best-preserved prints show three toes with blunt, triangular claws. The animals were probably like the plant eating Fabrosaurus (Lesothosaurus) known from Africa. This is the earliest evidence of ornithischian (meaning ‘bird-hipped’) dinosaurs so far found in Australia.
So, even if thousands of people have looked at a place before, there may still be something there that has been missed. It just depends on who is looking, how the light falls on the rock and whether it is dry or wet – this plus a little bit of luck as well. Therefore, every sedimentary rock is always worth second look.
Another geologist told me some years latter that he had seen more footprints outside of the gorge but he did not have a camera with him to photograph them. I have never had time to go back and track them down, so there could be more to be found for the next lucky tourist.
Note. If you find something in a national park please never take rocks – only photographs.
Dr Susan Parfrey works at the Queensland Museum. Before joining the museum, she worked at the Geological Survey of Queensland for 22 years, gaining an extensive knowledge of the palaeontology and geology of the state.
Reference
Thulborn, T 1993. In appendix B. The ancient rocks of Carnarvon Gorge. Department of Minerals and Energy, Queensland, Brisbane. Beeston, J.W. & Gray, A.R.G.