SYDNEY: An ancient river system buried 35 metres below the sand dunes Simpson Desert in Central Australia has been revealed by a team of Australian and American researchers.
This network of rivers and streams under the desert can be utilised for its valuable resources such as water in a sustainable way, the researchers said.
“We have gained insight into how the landscape works so we can manage water responsibly,” said researcher Michael Hutchinson from the Australian National University in Canberra, a main contributor to the study published in the latest edition of the Australian Journal of Earth Sciences.
Hidden under thick sand dunes
Scientists have always suspected rivers and streams once traversed the Simpson, but the thickness of the overlying dunes and bedrock in this area and limitations in landscape sensing technology have always held research back.
A team from ANU, after more than a decade of work, have conquered the thick overlying dunes and bedrock and developed complex new Digital Elevation Model (ANUDEM) software that successfully mapped the subtle topography that underlies the landscape of today.
The software models how water moves across the surface of the continent. It infers the location of the underground river system by joining the lowest points from ground-level elevation measurements, Hutchinson said.
Vast river system
Using their new software, the team from ANU mapped the course of the rivers buried roughly 35 m under the Simpson Desert for the first time. The rivers are vast, covering hundreds of kilometres, the researchers said.
It is estimated the rivers and streams are some of the oldest in the world, at least 50 million years old, from a time when the desert was greener and wetter than it is today.
The results looked right according to the team, as the underground rivers were mapped where they were expected to be according to current adjoining rivers in the area.
“The ancient drainage systems are thought to have originated in the wet climate of the late Cretaceous, they are that old,” Hutchinson said.
The discovery of the ancient rivers have highlighted the dramatic shift in landscape Australia has seen over time and “serves as a dramatic reminder of climate change,” said co-author Robert Craddock, from the Smithsonian Institute in Washington.
Buried river channels have proven to be valuable economic, ecological and agricultural resources in other continents.
Gold mines and wells in the desert
Heavy minerals such as gold and uranium could be associated with the ancient drainage systems, Hutchinson said. This map is likely to aid mineral exploration currently occurring in the area.
And the underground rivers could suggest places for wells in the future, Hutchinson said.
But humans aren’t the only ones that rely on this valuable resource – numerous plants and animals are sustained by this ground water, many of which are endangered.
Model may predict future landscapes too
Although the ANUDEM has allowed the researchers to peer into the past, the software is also being used to model the future, Hutchinson said. It is possible to predict what the future landscape might look like under changing climatic conditions.
“Their results tell us where the ancient rivers are in that region but not their age, their groundwater contents or the nature of their infilling sediments”, said John Magee, a geologist from ANU who also works in landscape mapping but did not contribute to Hutchinson’s study.
“The methodology developed by the researchers could undoubtedly be used to improve mapping of ancient river systems throughout the world”.
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