ANSTO scientists use radiocarbon-dating to help solve rock art mystery

ANSTO nuclear scientists have played a pivotal role in solving a 20-year mystery surrounding the age of ancient Aboriginal rock art found in the Kimberley region of Western Australia.

ANSTO scientists and University of Melbourne researchers joined forces to develop a new way to estimate the age of ancient artwork by collecting mud wasp nests from 108 rock art sites before ANSTO's radiocarbon-dating capabilities determined their age.

Scientists determined the Gwion-style paintings, commonly characterised by elongated, highly decorated, human figures, proliferated in the Kimberley about 12,000 years ago.

It is the first time scientists have been able to determine the age of the artworks, which have been the subject of research for more than 20 years.

Mud wasp nests, which are known to survive for tens of thousands of years, contain tiny amounts of carbon, mostly in the form of charcoal from bushfires, which can be radiocarbon-dated, providing an idea of the age of the adjoining rock art.

Using a new scientific approach, mud wasp nests overlying and underneath the paintings were collected, dated and then used to establish minimum and maximum age limits for the rock art.

This method of dating is now being applied to other styles of Aboriginal rock paintings and could prove useful in providing age estimates for other past human activity.

ANSTO chief executive Dr Adi Paterson described the method as a significant development in dating Aboriginal cultural heritage.

"This discovery was enabled through ANSTO's ingenuity accelerator technology," Dr Paterson said.

"This study is an excellent example of the many applications it has for nuclear science."

ANSTO scientist, Dr Vladimir Levchenko, was among the team of researchers who developed the method.

"The frequency in which nests were built make them capable of providing age constraints for archaeological features and rock art throughout that period, reaffirming this approach," Dr Levchenko said.

In all, 101 radiocarbon dates were recorded, of which 31 were older than 10,000 years, nine were older than 15,000 years and two were more than 20,000 years' old.