Clues to early life: Geologist Jonathan Giddings stands next to a rock stratified with layers of the 650-million-year-old reef.
Credit: University of Melbourne
SYDNEY: Geologists have discovered a fossil coral reef in mountains of the Australian outback. Last underwater 650 million years ago, it could provide fresh insight into the evolution of the earliest animals.
The University of Melbourne researchers behind the find report that it could reveal fossils of these primitive animals and also help trace the pattern of global climate change.
The reef is believed to have existed for between five and ten million years during a period of tropical climate squeezed between two major ice age events, also known as Snowball Earth events, said researcher Jonathan Giddings.
New species
"It provides a significant step forward in showing the extent of climate change in Earth's past and the evolution of ancient reef complexes – and it also contains fossils which may be of the earliest known primitive animals," he said.
The reef was discovered in the Northern Flinders Ranges in outback South Australia, said Giddings, who worked with Malcolm Wallace and Estee Woon from the university's School of Earth Sciences. It is the only known reef complex of this age anywhere in the world, with the closest in time being reefs around 800 million years old located in the Canadian Arctic, they said.
The scientists will present their findings at the Geological Society of Australia's Selwyn Symposium, at the University of Melbourne on Thursday.
"There is a good chance that the new fossils and organisms found in the reef will provide significant insight into the evolution of early multi-cellular life," said Giddings. "It could prove that life took more complex forms much earlier in history than we previously thought."
Tectonic forces
"From a climate change point of view, this reef provides an important record of what was happening in the ocean 650 million years ago," when the eastern part of Australia was still under water, added Wallace.
And if you're wondering how this once underwater reef is now located in a very barren part of inland Australia, Giddings said that the eastern part of the Australian continent – from the Flinders Ranges through to the current eastern seaboard – was once submerged under the ocean.
However, with the movement over millions of years of Australia’s tectonic plates, the reef has now been turned 90 degrees skywards from its once horizontal position. "This has exposed the whole one kilometre depth of the reef, from what was once its shallow water section right down to its deep water section," he said. "In effect, these tectonic forces have resulted in very ancient history being pushed up to the present."
With AFP.
