They come from beneath the Earth
The Ediacara Hills, in the west of the Flinders Ranges, are finally giving up a secret that could fill in the gaps of Charles Darwin’s theory of evolution and solve what is known as “Darwin’s dilemma”. Today, this secret is attracting people from around the world, including famed broadcaster and naturalist David Attenborough
Words Jade Gailberger
It feels like a million miles from anywhere but it’s the centre of something big. Something that could change the way we view how life developed on the planet. The Flinders Ranges lie 500km north of Adelaide. The land here is ancient. The time scales bend the mind. Somewhere around 600 million years ago this was the very edge of the continent of Australia.
But the secrets that lie in the Ediacara Hills, in the west of the Ranges, have only recently, in those vast geological terms, been given up.
Now they are attracting people like famed broadcaster and naturalist David Attenborough, as well as a variety of international scientists all making the long trek to try to examine the fossils of the soft-bodied organisms that used to live on the sea floor.
It is by examining these fossils that the visitors hope to fill in the gaps of Charles Darwin’s theory of evolution and to solve what is known as “Darwin’s dilemma’’. In his landmark book On the Origin of Species Darwin admitted his theory of evolution was contradicted by the existing fossil records of the time. He couldn’t explain the lack of fossils that would support his theory of evolution.
But in 1946, Reg Sprigg, a young South Australian geologist with a secret ambition to find fossils, was commissioned to check old lead and silver mines at the old Ediacara minefield. There he discovered fossil imprints resembling soft corals and jellyfish in sandstone rocks around the low hills.
The initial findings and their significance was reinforced about a decade later when amateurs found more fossil imprints – that have since given scientists a new understanding of the evolution of life on earth, and the preservation of soft tissue organisms on the sea floor.
South Australian Museum senior research scientist Dr Jim Gehling first became involved with the Ediacara fossils as a student at the University of Adelaide. He has spent the past 15 years working fulltime on the fossils and said the biggest discovery has been finding new fossil sites in the most unsuspecting of places. “Everyone always wants to find the biggest, the rarest, the oldest,” Dr Gehling says. “These are certainly the rarest and the oldest fossils you can see with a naked eye on earth. That makes it pretty spectacular because we really only just scratch the surface.”
The fossils in the Ediacaran period, named after its location, cover an interval of around 88 million years from 630 to 542 million years ago, and are preceded by skeletal fossils in the Cambrian period.
Around 30 other Ediacara sites are known across the world including Namibia in Southern Africa, Russia, Canada, the United Kingdom, Siberia and China. Dr Gehling says the fossils found in South Australia have not been found in any other country. “We get people from Oxford and Cambridge and Universities in North America and Europe and China coming to Adelaide because they want to look at our material and compare it to what they’ve got,” he says. “We hope to better understand how many of these animals survived into the next geological period and ultimately gave rise to things like us.”
University of California geology professor Mary Droser has been making annual trips to South Australia for 15 years with her children to excavate fossils at a property in Nilpena, with Dr Gehling.
Her work on the “world-class and world famous” fossils – which includes finding evidence of sexual reproduction – has been funded by NASA, National Geographic and the National Science Foundation, and even sparked the interest of naturalist and broadcaster Sir David Attenborough. “It was a blast taking him into the field because he was so excited,” Professor Droser says. “People all over the world want to come see it, and ultimately there will be other people working there. That would be our vision – also that it would be open to the public at some point.”
Excavation of fossils in the region involves taking the dirt off the top of sandstone beds, map the outlines of the rock on plastic and put the rocks – broken into pieces from earth movement – back together like a puzzle piece. “You would lift that rock and have an imprint of everything on the sea floor,” she says. “A phenomenal natural laboratory is sitting in your backyard.”
Professor Droser’s work has also inspired her children, Emily Hughes, 18, and Ian Hughes, 16, who have spent every summer school holiday – June to July – in SA.
Professor Droser says her daughter has even learnt about Ediacara in a biology class at school. “It’s pretty cool that here we are in California and there’s millions of kids every year reading about … Ediacara in the Flinders Ranges,” she says. “This is a huge, world famous part of South Australia’s heritage but it’s also an opportunity to talk about science and the history of life and evolution and even climate change.”
Dr Gehling says when people visit the Great Barrier Reef they’re seeing the top of the tree of life, as a result of the things that started in the Flinders and Mt Lofty Ranges about 500-600 million years ago.
He says it was the reason people visit the Flinders Rangers, and towns such as Hawker, Quorn, Leigh Creek and Arkaroola were ideal places for people to use as staging points to go out and begining to understand where life as we know it came from.
“For most of the year ordinary people can actually see that kind of geology and what we need is people in the districts of the Flinders Ranges to have enough knowledge and interest to introduce visitors to that without it just being collectors who want to come and souvenir,” he says.
“If (the fossils) are kept in place it means much more to the visitor and for that reason we are very keen to run programs with people in the Flinders Ranges to give them greater awareness.”