FACT SHEETS

Rewriting History: Australia’s oldest known campsite

20.10.17

Archaeologists, working together with Mirrar Aboriginal people, are unlocking some extraordinary secrets from Australia’s oldest known campsite. Latest dating techniques have established a new minimum age for arrival of the first Australians at least 65,000 years ago. This suggests Aboriginal people and megafauna co-existed for 20,000 years or more. Perhaps most profoundly, this re-sets the clock for the time when modern humans first left Africa; raising questions about who they mixed with along the way.

Imagine a time 65,000 years ago, when large parts of the world were locked under sheets of ice, and sea levels were 50 metres lower. Northern Australia was cooler and wetter. Megafauna – think massive hippo-sized marsupials, and formidable two-metre tall emu-like birds –roamed the landscape.

At this time, 20,000 years before modern humans had even reached Europe, the first Aboriginal Australians were already living around a rock shelter known as Madjedbebe on a sandstone plateau in Arnhem Land in the Northern Territory.

These people were expressing themselves artistically in what’s now considered to be Australia’s earliest known pigment processing. They were mixing ochre with reflective glitter-like powders to make vibrant paints – part of a complex ancient culture that western science is only just beginning to understand.

Scientist Dr Elspeth Hayes with Mark Djandjomerr at the dig site. Dominic O Brien/Gundjeihmi Aboriginal Corporation
Three-layers of discovery
Artefacts at Madjedbebe were found in three bands. The lowest at 2.6-2.15m under present day ground levels, is the area of oldest occupation.
Rewriting history
Researchers have evidence to push back the age of human occupation of Australia by about 18,000 years to 65,000 years ago.

“For the local Mirarr Aboriginal people, they know they’ve always been here”

Unlocking a secret history

Recent archaeological work at Madjedbebe carried out by researchers from the Universities of Queensland, Washington, Notre Dame and Wollongong, is now unlocking some of the secret history of the lives, and indeed, the innovation of these early settlers.

Professor Zenobia Jacobs is one of the key researchers in the study of Madjedbebe.

“People employed sophisticated stone tools like edge-ground hatchet heads made by grinding,” Professor Jacobs said.

“They used these to cut timber, and possibly to help access food that was difficult to source.”

Archaeological evidence from what’s thought to be the world’s oldest known seed-grinding stones, and an ancient hearth (fireplace) tells us people here were also harvesting, grinding and cooking plant foods like fruit seeds, yams, and Pandanus nuts.

To give some context, this was all happening at least 60,000 years before the first pyramids of Egypt were even a twinkle in Pharoah Djoser’s eye.

Excavations through many layers at the site. Dominic O Brien/Gundjeihmi Aboriginal Corporation

Going back to Madjedbebe

Madjedbebe (previously known as Malakunanja II) was initially excavated in 1973, and again in 1989. Stone tools and ground ochre examined then were thought to be 50,000 to 60,000 years old.

These findings were contentious because of a lack of details describing the artefacts, and possible disturbance to samples and the implications for dating them.

The archaeologist’s toolkit has expanded since then, as technology and methodologies have advanced.

Archaeologists knew Madjedbebe was a site of great importance. They knew it was very, very old and highly significant to Mirrar Aboriginal traditional owners.

In fact, it turned out to be even older than originally thought, and way older than any other Australian archaeological site that’s been discovered so far.

Going back to Madjedbebe

Madjedbebe (previously known as Malakunanja II) was initially excavated in 1973, and again in 1989. Stone tools and ground ochre examined then were thought to be 50,000 to 60,000 years old.

These findings were contentious because of a lack of details describing the artefacts, and possible disturbance to samples and the implications for dating them.

The archaeologist’s toolkit has expanded since then, as technology and methodologies have advanced.

Archaeologists knew Madjedbebe was a site of great importance. They knew it was very, very old and highly significant to Mirrar Aboriginal traditional owners.

In fact, it turned out to be even older than originally thought, and way older than any other Australian archaeological site that’s been discovered so far.

What Lies Beneath: An archaeological treasure trove

Artefacts at Madjedbebe occurred in three bands. The lowest band at 2.6 – 2.15 metres under present day ground levels, is the area of first (oldest) occupation.

It contained a treasure trove of archaeological material, giving evidence to push back the age of human occupation of Australia by about 18,000 years to 65,000 years ago.

Some of the most fascinating artefacts found at the rockshelter include:

  • pieces of sheet mica wrapped around a large yellow ochre ‘crayon’
  • the world’s oldest known use of reflective pigments
  • the world’s oldest known edge-ground hatchets
  • an ancient campfire and grinding stones
  • a (now extinct) thylacine (Tasmanian tiger) jaw bone coated in red pigment (found in upper, more recent layers).

“In Africa, when we excavate a site we can easily get hundreds of thousands of artefacts, really rich, the same in Europe” Professor Jacobs said.

“In Australia when you excavate a site, it’s usually sparse, but this site is different. This site is incredibly rich. Just in the lowest dense occupation layers there were more than 11,000 artefacts. In Australian terms, that’s extraordinary”.

“The density of the artefacts suggests this was a place where people lived, we don’t see any gaps in the sequence. It’s a pretty continuous sequence from 65,000 years ago right up to the present, so it’s obviously a special place where people have always been”.

Professor Zenobia Jacobs used sophisticated dating technology to test samples from Madjedbebe

Seeing the light

When you’re rewriting the history books, it’s important to get things right.

That’s why Professor Jacobs used Optically Stimulated Luminescence (OSL) dating, rather than the better-known radiocarbon dating method, to scrupulously test and retest samples from Madjedbebe.

“We couldn’t get it wrong,” she explained. “There was too much at stake, so we had to make sure that we did the best job we possibly could with the available technology we had. Everything had to be triple checked.”

“Radiocarbon dating is limited, it only goes back, if we’re lucky, to 50,000 years. Of course, we’re interested in lots of things that are older than 50,000 years.”

Put simply, OSL dating techniques provide an estimate of the time since mineral grains were last exposed to sunlight.

Professor Jacobs and her team used this method to painstakingly analyse 28,500 individual grains of quartz from Medjedbebe.

She likens grains of sand as tiny rechargeable batteries.

“You have these little grains moving around in the landscape – in effect, little batteries”, she said.

“When they’re exposed to sunlight, the battery gets drained.

When they’re hidden from sunlight, they start to build up energy as electrons are trapped in the crystal lattice.

And when we expose it to sunlight again, it gets drained. So really, the last time it gets exposed to sunlight is the last time it was drained.”

“Sand gets buried in the archaeological site, and the mineral grains build up energy. We go into the site and take the sample in the dark – because, of course, if we expose it to light, we reset the signal.”

Samples are taken back to the lab. It’s meticulous work.

“Everything we do – because it’s so sensitive to sunlight – we have to take back to the lab.

It looks like a photographic darkroom. We open the samples, we go through a vigorous process of cleaning them, and we do everything in that darkroom.”

The work is labour-intensive, taking years to complete.

“It’s certainly not something we put into a machine, and ‘ping’ out comes a number,” Professor Jacobs said.

Axes and grinding stones were found in the excavations. Glenn Campbell/Gundjeihmi Aboriginal Corporation
Ben Marwick, Univeristy of Washington, showing the dig site to visitors. Dominic O Brien/Gundjeihmi Aboriginal Corporation

Is it possible that modern humans were living in Australia even earlier?

Why are archaeologists saying the site is at least 65,000 years old?

“We’re calling it a ‘minimum age’ as there were some artefacts below where the 65,000 year old samples come from,” Professor Jacobs said.

“We need to check whether those fewer artefacts lower down are actually in primary context, make sure we understand that they were deposited there and not moved down from higher-up,” said Prof Jacobs.

The other reason the team refers to a ‘minimum age’, is simple.

“What’s the chance you’ve found the oldest of anything? There’s always the possibility of something older somewhere. It’s very difficult to pinpoint the first. It’s the same with extinctions. What’s the chance the fossil you’re dating is the last of that species?”

So, it’s highly likely there are other undiscovered sites that will cast new light into the future.

“If you think how large this continent is and how many sites we’ve excavated in a systematic manner, it’s just a handful – so there’s definitely an untapped resource there.”

The number itself, 65,000 years, is very much a Western construct.

“For the local Mirarr Aboriginal people with whom we collaborate at the site, they know they’ve always been here.”

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