The Best Australian Science Writing 2013 (13 page)

For the Jawoyn, putting scientific flesh on the bones of their ancestral beliefs – their Dreamtime – is compelling. Like elders of every culture, they are consumed by the responsibility to pass their knowledge to the next generation. The Jawoyn Association – established in 1985 to develop unity and economic independence for the Jawoyn – is one of Australia's most successful Indigenous business operations. Even so, this next generation is at risk. The remaining holders of traditional knowledge – fractured and fading as it is – are few and dying. And the Jawoyn youth still run the gauntlet of ills that beset all marginalised Aboriginal communities – drugs, alcohol, violence and the easy slide into welfare dependence. Community leaders believe science will help form a bridge for the next generation, helping connect the ancestral Dreamtime to modern times and, in the process, nurture self-esteem and ambition. ‘We want our kids to grow up to be archaeologists, geologists, helicopter pilots,' says the Jawoyn Association's CEO, Preston Lee.

And if science can offer something to the Jawoyn, the Jawoyn have something to offer science. Geneste explains by phone from his 300-year-old stone cottage in the south of France: ‘We don't have anyone to explain Chauvet Cave to us. In France, these are sites with no memory, no life. With Gabarnmung, we are lucky. There is the living culture, the memories. The Jawoyn can help us build a new knowledge.'

Geneste offers an example: ‘We found a kangaroo mandible covered in ochre and showed it to Margaret. The next morning she said, “I remember now. It was a tradition when a young
hunter killed his first game. He wrapped it in paper bark, put it in a cave and preserved it under the authority of an Auntie.” Together we are finding out things about their history.'

* * * * *

Helicopter pilots are well-regarded by the Jawoyn community. Indeed, if it were not for helicopter pilots, Gabarnmung would be just another cave of forgotten dreams. In 2006, pilot Chris Morgan was flying his chopper across the sandstone escarpment. Next to him sat sandy-haired, easy-going Ray Whear dressed in grungy shorts and a T-shirt, one of the Northern Territory's most successful businessmen, who now manages the cultural and environmental affairs of the Jawoyn Association.

The chopper roared as Whear trained his eyes on a landscape seemingly untouched by European contact. He saw the sparkling Katherine River snaking through the broken brown plain below and the great pale-green expanse of savannah woodlands. But what he and Morgan were really interested in were the rocky outcrops that dotted the landscape. They were returning from a bushfire management meeting and had decided to indulge one of their favourite pastimes – rock-art spotting. The clue, says Whear, is the shine on the rocks. It might mean lots of human bottoms have graced them, perhaps for a ceremony involving art. Whear and Morgan have had some spectacular finds – like an ochre painting of Genyornis, a giant flightless bird that's been extinct for 45 000 years. Could the painting itself be that old? So far, there has been no way to date it.

This time, Whear and Morgan once again spotted some rock shine. They zeroed in to find their chopper face-to-face with six top-hatted gentlemen gazing at them from the deck of a clipper ship. The metre-high white ochre painting formed part of a gallery of sailing boats, barramundi, emu, yam figures, dynamic
figures, X-ray kangaroos and crocodiles, rainbow serpents and the now extinct Tasmanian tiger! But the real prize awaited them. Back in the chopper they trained their eyes on the surrounding area and some 5 kilometres away noticed an unusually large rock shelter. They landed and walked into one of the richest collections of Aboriginal art ever found. Like the Sistine Chapel, the ceiling of the expansive rock shelter was a mural of breathtakingly vivid and bold works of art – hundreds of them. And the paintings extended up and down 36 remarkable sandstone columns that, like the pillars of a temple, appeared to support the cave.

When they returned with two elders, Wamud Namok and Jimmy Kalariyya, it was an emotional moment. The elders remembered visiting the site as children, that its name was Nawarla Gabarnmung – meaning ‘hole in the rock' – and that its traditional owners were a Jawoyn clan called the Buyhmi. Margaret Katherine is a Buyhmi elder and it was her decision in 2010 to invite a team of international archaeologists and rock art experts to explore the cave. The first invitation went to Bruno David. His reputation had preceded him, particularly his sensitive work with communities in Cape York and the Torres Strait islands.

I met David in October 2011 during a tour of the Gabarnmung cave when I was privileged to join a select handful of visitors who have so far had that honour. David has an adventurous, athletic look. He wears hiking gear, is of medium athletic build, has slightly receding long dark curly hair, olive skin and luminous blue-green eyes. I'm guessing 40-something. His accent is hard to pick. It turns out to be highly eroded French, but you'd be hardpressed to figure out his nationality. David could be a native of many places.

What strikes you most about him is his gentleness. It's no surprise that Margaret Katherine invited him. She has given him and his two-year-old son ‘skin' names – part of her people's social structure – and he calls her ‘Auntie', a mark of respect. David's
connection with the Jawoyn is clearly more than just academic.

Geneste has also been given a skin name. ‘More and more it's not just fieldwork,' he says. ‘We have conversations around the fireside, at camp, in the early morning and before we go to sleep. The exchange of worlds is happening.'

But it was not always so. Archaeologists and Aboriginal communities have a troubled history. The late 1960s saw remarkable discoveries of skeletons dating back 30 000 years or more that told the story of the ancient colonisation of Australia. There was also evidence of the world's first ceremonial burial with an ochredaubed 30 000-year-old skeleton unearthed in Lake Mungo, 760 kilometres west of Sydney. These were archaeological treasures, but also the remains of ancestors. The Aboriginal custodians demanded reburial and with it buried much of Australian archaeology for the next couple of decades. Australian archaeologists went off to Egypt and other places to ply their trade. Now, very carefully they are making their way back, cautiously awaiting invitations to collaborate with traditional owners.

At the airport, en route to Darwin, I discuss Aboriginal art with David and he takes me straight to the heart of the matter. I don't get some detached academic description of technique or style. ‘Country is one of the most powerful notions,' he says. ‘We don't talk about time; we talk about place. The connection with ancestors is unbroken.' I begin to understand: the painted rocks and caves, indeed the entire landscape, is a timeless stage where the veil between present and past is drawn back.

For all David's empathy, he is also a very hard-nosed scientist. Indeed, to survive in archaeology, he has to be. All science is brutal – ‘organised scepticism' – some say. But archaeologists are positively gladiatorial when it comes to challenging each other. Whether their findings stand or fall often depends on how meticulously they can measure the age of the material they find. ‘We don't want anything iffy,' David says.

* * * * *

A Google search reveals claims for Australian rock art being up to 40 000 years old. But as Geneste tells me, ‘This represents the philosophical divide; art is art and science is science.' Art experts might be a little fast and free with their dates but even the scientific dates leave some doubt. It's hard to carbon-date very old paintings because pigments in organic material, such as beeswax or charcoal, usually don't last – unless they are entombed in a dark sealed cave like those at Chauvet. (Carbon-dating can only be used to date substances that were once alive since it measures the ratio of carbon-14 to carbon-12, a ratio that declines once an organism dies.) Ochres endure but don't carry organic material, so they can't be carbon-dated. Hence indirect methods have been used which do tend to be iffy. For instance, a piece of ochre-coated rock was found in the charcoals of a fire site in Carpenter's Gap in the Kimberley region of Australia's northwest. Those charcoals gave a date of close to 40 000 years. But was the ochre on the rock really the remains of a painting or a natural mineral deposit? ‘Unless you have an image, you can't be sure,' says David.

Mud wasps offer another means of dating rock art. Wasps have a penchant for building their nests in the same rock shelters favoured by Indigenous artists and often plaster them right on top of the paintings. Sometimes those nests are extremely old, so old they have become fossilised.

In 1997 Bert Roberts, now at the University of Wollongong, pioneered a method for dating the individual grains of sand buried in ancient wasp nests known as OSL (optically stimulated luminescence). In the darkness of the nest, electrons in the sand grains, nudged by background radiation, become entrapped in the sand grain's quartz crystal lattice. The longer they are buried, the more electrons are trapped. Roberts plucks these buried sand
grains from the wasp nest at night with the help of a red-light torch. Back at his lab, he places the individual grains in a photon counter and zaps them with light, freeing the trapped electrons. The number of photons released equates to the number of years elapsed since the wasp first entombed the sand grain in her nest. So the painting underneath the nest must be even older. In 1997, in a paper published in
Nature
, Roberts used the technique to date a mulberry-ochre-coloured human stick-figure at King Edward River Crossing in the Kimberley region of northwest Australia. He reported a date of at least 17 000 years. Most archaeologists accept it as the oldest date for Australian rock art, though there are still reservations – even from Roberts himself.

That's why the painted fragment from the floor of the Gabarnmung cave is causing so much excitement. There is a clear image. ‘No one doubts that it's a piece of a painting,' says David. It is very finely drawn. It could even be part of a ‘dynamic figure' – the local stick-figure style that resembles Kimberley art styles like the Bradshaw Paintings. Says Roberts, ‘When it comes to getting dates, the below ground evidence [referring to the buried art fragment] may be better than what's above.'

The dark pigment itself is charcoal – and because it has lain in the ground for thousands of years, it is possibly as well-preserved as the charcoal pigment that inscribes the rhinoceros at Chauvet Cave. A mere pinpoint of charcoal was required to get the date on that rhino. Perhaps a mere pinpoint of charcoal will also suffice from the Gabarnmung fragment?

Unfortunately, it's rarely so easy. There are many pitfalls waiting to ensnare the archaeologist who dares to date rock art. And David is determined not to be ensnared. His meticulousness is on full display here in the Monash lab. Here I witness meticulousness on steroids.

One possible pitfall is that when carbon-dating expert Fiona Petchey scrapes the charcoal pigment from the rock she will also
take off microbes that have grown there. Microbes make organic compounds, such as calcium oxalate, that will corrupt the true carbon date of the charcoal pigment. That's why colleague Mark Eccleston has brought along his X-ray fluorescence gun. It can detect the calcium from calcium oxalates.

Eccleston trains the shiny steel gun just above the rock fragment. For a minute or so, two red lights flicker around its barrel as if contemplating the object below. They stop and the gun delivers a verdict. There is a miniscule amount of calcium: 108 parts per million. ‘At first look, it seems there is nothing to worry about,' David explains. Margaret Katherine says, ‘I'm so excited. I respect my country. That's why I want you to find out how many generations ago people did this painting.'

The excitement builds. Petchey in her white lab coat now sits on the lab stool peering down at the rock fragment under the microscope. She holds a scalpel and starts to peck at the black cross decorating the rock surface. We all watch silently. More pecking and some halting, doubtful comments from Petchey … It seems we have an anticlimax.

Petchey ceases her pecking. She says, unfortunately, that she simply cannot scrape off the pigment as it is too solidly bound to the rock. She asks if she may take the fragment to Waikato University so that the specialist chemist there can extract the pigment in the lab. They may be able to combust the dark pigment and test that it is indeed charcoal. If that fails, they might also try to get a date on the charcoal residue that dusts the upper surface of the rock. Margaret Katherine gives her permission.

Epilogue

I called David for an update on the rock fragment. He had just received the raw data. They could not extract enough of the pigment that had painted the cross for analysis. But they had been able to date the charcoal dusting the back of the painting. It was
28 000 years old. The tiny painting had not won the big prize, the one that would put it on the cover of
Nature
or
Science
. Chauvet's rhinoceros still rules. But 28 000 years, David points out, is still the oldest scientifically established date for an Australian painting, although the finding has yet to enter the gladiatorial arena of peer review and publication.

But it's not the end of the story. Digging at Gabarnmung has just begun. Says Geneste, ‘I think there could be artwork as old or older than Chauvet'. For the next dig David will also be bringing in Bert Roberts who, in the 1990s, together with the late Rhys Jones, identified Australia's oldest sites of human habitation just tens of kilometres away: Nauwalabila and Malakunanja II rock shelters. Those ages came in at 50 000 to 55 000 years. At Gabarnmung, Roberts will measure the date of individual quartz grains that were buried together with the painted rock fragment. He told me, ‘I've been waiting 20 years to get back to that region. This is where all the action is happening'.