Monday, 29 April 2013

Digital technology resurrects ancient rock art

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Rockart mitchellRoo2An overpainted rock art image from Mitchell Plateau in the Kimberley. Image: Kimberley Rock Art - Volume One: Mitchell Plateau Area by Mike Donaldson, Wildrocks Publications 2012.STUDENTS at the University of Western Australia are using digital photography software to capture ancient indigenous artwork which has been painted over to help determine how art influenced early Kimberley society.

The investigation is being led by Archaeologist Peter Veth who is the inaugural Ian Potter Chair of Kimberley Rock Art at UWA.

“We are trying to understand how the art functions in different phases of initial colonisation of the continent, the development of a Kimberley economy and society, a regional style system, how that then developed with different language families through time,” Professor Veth says.

“There’s a very poor handle on the actual ages and dates – dating the art will involve a battery of new techniques.”

Prof Veth’s post-graduate students are using DStretch, a digital photography software developed for medical imaging to view ancient art that has been painted over.

“You can literally just stand there and peel through entire scenes, and entire episodes, of art production,” he says.

Prof Veth described the various overlays at northern Kimberley painting sites to illustrate how the different historical phases cover one another.

“The most recent phases like Wanjina clearly overlay much earlier ones like the Gwion Gwion or Bradshaw, but they again overlie very early engravings and painted complexes,” he says.

“Probably the [earliest] are cupules: small ping-pong-like depressions in the rocks.

“After that we get tracks and geometric motifs engraved, which are part of a larger Australian tradition called Panaramitee."

Prof Veth says they will deploy a portable XRD [X-Ray Diffraction] device which is currently being developed overseas.

He says the technology will help generate characterisations of early pigment art which is covered by skins of oxalates [natural fruit chemicals] which can be dated.

“We will be using a range of techniques to extract infinitesimally small amounts of carbon down to 20 micrograms from pigments to do AMS [Accelerator Mass Spectrometry] dating,” Prof Veth says.

“There are other techniques being used at the moment in the Kimberley such as uranium-thorium dating of oxalate skins.

“We’re going to be using those in MOUs [Memoranda of Understanding] with dating facilities at ANSTO, their two accelerators, a range of equipment at University of Melbourne and then the OSL [Optically Stimulated Luminescence] facilities at University of Woolongong, and [the] plasma oxidation unit we’re building here at Perth to pre-prepare those tiny samples of carbon from pigments.

“[We will also] be working with palynologists, looking at changes of vegetation structure.”

Professor Veth is commencing talks with the Kimberley Land Council to initiate collaborative projects with Indigenous ranger groups.

This story pertains to deliveries in theme 3 of the Kimberley Science and Conservation Strategy.

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