Archaeologists have unearthed a cache of stone tools at Lake Gregory near Halls Creek used by Australia's earliest inhabitants 50,000 years ago.
The tools, a selection of stone blades and "cores" from which blades were chipped off, were among the oldest evidence of human activity in Australia, said Peter Veth, of the Australian National University in Canberra, who led the discovery.
Some of the 15 artefacts are between 45,000 and 50,000 years old, meaning they date back to the time when humans first set foot on the continent.
The discovery is consistent with a picture in which Aboriginals arrived in Australia around 50,000 years ago, after their ancestors left Africa roughly 10,000 years earlier.
The Lake Gregory tools are roughly the same age as human remains found at Lake Mungo, NSW, as well as discoveries at sites in the Northern Territory, meaning the entire continent must have been colonised relatively quickly.
The first Aboriginals would have had seafaring skills as well as the ability to make tools, catch and butcher animals, process a wide variety of plant species and survive both desert and monsoon conditions.
"These were a people who were able to master any kind of environment," Professor Veth said.
Today, Lake Gregory is a relatively small oasis on the edge of the Great Sandy Desert, but 50,000 years ago it was 10 times its current size.
The region would have been hit with torrential downpours and frequent floods, in contrast with today's desert.
The huge lake would have provided plentiful food, including freshwater mussels, birds and fish, as well as attracting other animals such as emus and kangaroos.
Professor Veth, whose finding are published this week in the journal Australian Archaeology, said he hoped to find tools used for grinding plant material such as seeds, although only blade-related tools had been found at the site so far.No human remains are expected to be recovered from the site, because they would have been destroyed by the formation's alkaline conditions. But Professor Veth said further excavation at nearby sites could yield human bones.