The lower Murray River was once a long, mostly still lake that snaked hundreds of kilometres upstream, supporting a large Indigenous population with abundant fresh water, fish and birdlife.
Scientists have identified the previously unknown body of water, dubbed Lake Mannum, from cores of clay and mud sediment laid down between 5000 and 8000 years ago. They say the findings also offer clues to how the Murray-Darling Basin may change in a rapidly warming world.
The researchers had been studying the reason for the collapse of river banks during the Millennium Drought, and the discovery of the lake “came as a real surprise”, said Tom Hubble, an associate professor at the University of Sydney and one of the authors of a paper published on Wednesday in Scientific Reports.
“It would have resembled very closely a long fiord,” Professor Hubble said. “In what we think of as a pretty arid environment, it would have been easy to get lots of fresh water, and there would have been abundant resources to support a large [human] population.”