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Posts Tagged ‘carbon dating’

110784674_mineral-nc

Photo: Damien Finch et al
Mud-wasp “nests go hard and mineralise over time,” reports the BBC. “(1) Dating nest material on top of the paintings gives a minimum age only.” (2) Removing the nest allows researchers to ascertain the maximum age.

Prehistoric cave paintings, it seems, still have secrets for the enterprising to unravel. Researchers, with the active support of the local Aboriginal community, recently learned that calcified wasp nests could help determine when some of those paintings were created.

Jonathan Amos reported at the BBC, “When the veteran telecoms engineer Damien Finch went on a three-week bush walk in Australia’s Kimberley region, he became enthralled with its rock art. On his return home, he tried to find out more about these enigmatic aboriginal paintings and engravings.

” ‘I couldn’t believe how little was known about them; we didn’t even know how old they were,’ Damien said. ‘It seemed disrespectful that scientists hadn’t studied this stuff more; it was downplaying the importance of the culture,’ he told BBC News.

“Now, 10 years on and in his 60s, Damien is putting that right. He’s approaching the end of his doctoral research on the topic, and in [a February issue of] Science Advances journal, has published his own efforts to age the Kimberley’s so-called Gwion figures.

“These feature finely painted human forms, often in elaborate ceremonial dress and carrying spears and boomerangs. It was thought they were painted some 16,000 years ago, but the University of Melbourne investigator has been able to show the likely age is [about] 12,000 years ago.

“Dating rock art is really hard. Aboriginal artists use iron oxide pigments (ochre) which contain no organic material and are therefore resistant to any radiocarbon analysis.

“Damien has got around this by studying instead the scraps of organic matter stuck on top of and underneath the paintings. And for this, he’s working with wasps. In particular, the ones that build nests out of mud. …

“When the female wasp gathers her mud supplies she inevitably picks up fragments of charcoal from the Kimberley’s fire-prone landscape. And this charcoal can be radiocarbon dated. … Material that smothers pigment gives a minimum age; underlying material provides a maximum age.

“A distribution of dates from many locations enables an estimate to be made for when the Gwion style was in vogue. …

“The paintings [Damien] and his team have been working on are, of course, sites of immense cultural significance. All the sampling was guided and approved by representatives from the traditional owners of the artwork.

‘We couldn’t have done what we did without their active support and encouragement,’ ‘Damien told BBC News.

“He’s hopeful the mud-wasp dating technique can now be used at more locations right across the north of Australia, and perhaps at other rock art locations in the Americas and Europe.”

More at the BBC, here.

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