Australia's First Peoples
In July 2017, evidence was published that sets the timing of when Australia’s First Peoples arrived in Northern Australia back to 65,000 years ago. This is much earlier than the previously accepted date of 47,000 years ago.
The evidence comes from a rock shelter site, Madjedbebe, located on the traditional lands of the Mirarr people and surrounded by Kakadu National Park. The site was excavated by an international team in partnership with the Mirarr Traditional Owners. Although the shelter has previously been investigated a couple of times since the 1970s, the most recent survey aimed to resolve some scepticism within the science community on the accuracy of the former estimates, which implied ages of 50,000 or more years.
As such, the methods for dating used in this survey are much more detailed and robust. Although radiocarbon dating was suitable for items in the younger two levels of the dig, it is limited to estimates younger than 50,000 years, so another method was required. For the older, deeper parts of the site, the team used optically stimulated luminescence (OSL). This technique estimates the time elapsed since grains of sand were exposed to sunlight and can accurately estimate dates up to around 150,000 years ago.
To further ensure the robustness of the study, multiple samples were analysed by independent laboratories and the results compared. The resultant large dataset of dating estimates for multiple artefacts led to the consistent estimate of 65,000 years.
The site is rich with artefacts, with at least 11,000 items found in the lowest, most dense layer of the site. In addition to showing the deep antiquity of Aboriginal occupation, the site also reveals new evidence on the technology and lifestyle of the first settlers. One particularly interesting find is the world’s oldest ‘ground-edge’ stone hatchets, along with seed grinding tools and stone points that may have been spear tips. These firmly place Australia’s first arrivals as some of the most technologically advanced people at the point of settlement.
Interestingly, the revised timeline now places Australian Aboriginal people living at Madjedbebe at the time when the now extinct megafauna (giant animals) roamed the country.