What evidence do archaeologists use to study pre-contact Australia?

Across Australia’s varied environments, archaeologists have uncovered numerous scatters of stone artefacts that speak to the long presence and skill of early toolmakers.

At Madjedbebe in Arnhem Land, excavations led by Chris Clarkson and colleagues from the University of Queensland and the Gundjeihmi Aboriginal Corporation unearthed over 10,000 artefacts buried in deep stratified layers, which include flaked stone tools, ground-edge axes, and ochre fragments.

When they applied optically stimulated luminescence (OSL) dating to sand grains, researchers worked out that human occupation at the site had begun at least 65,000 years ago. 

To understand how people adapted their tools over time, archaeologists have examined microliths and backed blades, along with grinding stones recovered from various inland and coastal sites.

For example, grindstones that were found at Cuddie Springs show residues of starch grains and ochre, which include evidence of native grasses and seeds, which suggests that Aboriginal groups processed plant foods and created pigments for ritual or artistic use.

The site has yielded dates ranging between 30,000 and 36,000 years ago, though some researchers have raised concerns about the reliability of the stratigraphic layers at the site and whether artefacts and megafauna bones were disturbed by natural processes.

As a result, these tools provide information about both diet and ceremonial customs. 

Across rocky cliffs and caves, as well as rock shelters, Aboriginal artists created painted and engraved images that preserve stories of ancestral beings and daily life, along with ceremonial knowledge.

At sites in Arnhem Land, multiple overlapping layers of pigment, some of which are covered by mineral crusts or wasp nests, have allowed researchers to use radiometric dating to work out a timeline of artistic production that spans at least 20,000 years.

For instance, in the Kimberley region, Gwion Gwion figures appear as finely detailed, elongated humans adorned with headdresses and tassels, which differ from the internal anatomical images typical of the X-ray style in the Northern Territory.

Researchers estimate that some Gwion Gwion paintings date to between 12,000 and 17,000 years ago, although other studies propose lower estimates of 5,000 to 12,000 years, and debate continues about their precise age and cultural origin.

As such, regional artistic traditions help show cultural variation across time and place.

More importantly, the content and style of rock art show spiritual beliefs tied to the Dreaming, a body of knowledge that Aboriginal custodians continue to teach today.

Along estuaries, river mouths, and coastlines, large piles of shell middens provide a relatively clear record of marine resource use and seasonal gathering.

At Wathayn in northern Queensland, midden layers that can stretch several metres deep and that can weigh dozens of tonnes include shells, fish bones, charcoal, and stone artefacts.

By conducting radiocarbon dating on organic materials within the middens, archaeologists were able to establish that local groups had returned to the site repeatedly over thousands of years.

Comparable midden sites at Keppel Islands and Cape Otway show similar patterns of long-term coastal settlement and use.

In addition, the presence of burnt kangaroo bones, turtle shells, and emu bones suggests that Aboriginal hunters targeted a wide range of animals that varied according to their location.

Charred eggshell fragments from the extinct Genyornis found in central Australia have dates of around 45,000 years ago and indicate early human interaction with megafauna, although some scholars have questioned whether natural fires could have caused the same burning patterns.

These findings are part of an ongoing wider debate about human involvement in the extinction of Australia's Pleistocene giant species.

As a result, archaeologists use this evidence to explore both human dietary choices and environmental impact.

At Lake Mungo, the discovery of two ancient burials changed archaeological understanding of ritual customs in Pleistocene Australia.

Mungo Man was buried with ochre around 42,000 years ago, and Mungo Lady's cremated bone fragments were among the oldest known cremations in the world, and together these burials suggest detailed funerary traditions during the last Ice Age.

Geologist Jim Bowler discovered both individuals, and this helped lead to the listing of the Willandra Lakes Region as a UNESCO World Heritage site.

Importantly, both individuals were intentionally buried with signs of ceremony and respect, which shows a developed system of belief.

Elsewhere, skeletal material that was uncovered at other sites provides information about age, health, injury, and activity patterns.

For example, close analysis of limb bones and dental wear allows archaeologists to infer diet and workload, along with patterns of mobility.

In many cases, grave goods, such as stone tools, ochre, or shell beads, suggest a belief in the spiritual significance of death and possibly an afterlife.

Given this, burials provide a rare view of both personal identities and social values.

Across many regions, layers of charcoal that were preserved in sediments offer information about how Aboriginal peoples used fire as a tool to manage the land.

At Puritjarra in the Northern Territory, archaeologists identified a continuous series of hearths and charcoal-rich layers that span more than 30,000 years, which include at least 18 separate fire features.

When paired with pollen and phytolith analysis, these layers show deliberate use of low-intensity burns to maintain open grasslands, encourage animal grazing, and prevent very intense wildfires.

Since changes in vegetation coincide with peaks in charcoal deposition, many researchers conclude that fire-stick farming techniques likely changed environments over time.

In other locations, botanical remains trapped in soil layers, such as seeds and husks, as well as tuber fragments, show how foragers adapted to shifting climates and made use of native plant resources in very deliberate ways.

Therefore, environmental data expands understanding of how Aboriginal groups sustained their lifeways through ecological knowledge.

In arid and semi-arid regions, the discovery of non-local materials shows the existence of wide exchange networks that likely operated over long periods.

Baler shells from coastal waters have been found hundreds of kilometres inland, and ochre from Wilgie Mia travelled across entire cultural regions.

Specifically, Wilgie Mia is located in Western Australia and is one of the largest and oldest known ochre mines in the continent, with evidence of extraction dating back over 30,000 years.

Archaeologists have traced the movement of such items through geochemical sourcing techniques, which connect artefacts to their geological origins with great accuracy. 

To explain how such materials reached faraway locations, researchers argue that Aboriginal people maintained ceremonial and trade routes along which knowledge and resources travelled, together with the people who carried them.

For example, the distribution of ground-edge axes and distinctive tool types suggests regular interaction between communities separated by deserts or mountain ranges.

Along these pathways, which often followed songlines such as those used in the exchange of pituri or Kimberley stone points, ideas and rituals were transmitted alongside goods.

As a result, the archaeological record shows ongoing contact between groups, even in remote inland areas.