Drowned land off Australia was an Aboriginal hotspot in last ice age, 4,000 stone artifacts reveal

The discovery underscores the "long-term connections" that Indigenous peoples have to modern-day Australia, said David Zeanah, an anthropologist at California State University, Sacramento and lead author of a new study describing the analysis.

The findings show "a surprising amount of diversity in stone tool composition over a relatively small area," said Tiina Manne, an archaeologist at The University of Queensland in Australia who was not involved in the research.

(Image credit: Google Maps)"The open sites provide clear links to the mainland geologies, and that infers that people were using the coastal plain that's underwater now," Zeanah said.

The team discovered that these stones were water-worn, suggesting that before they were crafted into grinding tools, they had been hand-selected from stream beds or tidal regions, perhaps from coastal flats or rivers that may have run across the exposed plain that once connected Barrow Island to mainland Australia when sea levels were low.

The presence of those grinding stones on Barrow Island supports the idea that mass movement and knowledge sharing unfolded for thousands of years across this landscape, the study authors said.

"It provides a record of coastal and hinterland desert landscape use by Aboriginal peoples during a time period that is virtually unknown from elsewhere on the continent — because other similar coastal-hinterland areas now lie drowned beneath the sea."