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X-ray specs: viewing artefacts in a new light

By: Rebecca Hancock, Category: Science, Date: 04 Jun 2009

Using the latest technologies, archaeologists are digging for new insights into Indigenous trading routes.

Peter Grave using PXRF

Cate Lowe © Australian Museum

By Dr Peter Grave and Dr Val Attenbrow

Using the latest technologies, archaeologists are digging for new insights into Indigenous trading routes. Australian Museum Archaeologist Dr Val Attenbrow and colleague Dr Peter Grave from the University of New England discuss their latest research.

Volcanic stone for making axe heads and other tools was an important resource for Aboriginal people across Australia. Suitable sources of stone were abundant in eastern Australia where it was heavily exploited and then widely traded from place to place.

By linking artefacts back to the source quarries, archaeologists can begin to reconstruct the trading routes and economies of cultures that have since all but vanished.

From the 1960s archaeologists formalised the use of analytical 'fingerprinting' techniques for tracing artefacts to their likely sources. Studies verified the existence of long-distance exchange in eastern and central Australia. Unfortunately, the techniques used at the time required a level of damage to artefacts that is unacceptable today, and recent work in Australia has, understandably, avoided such destructive methods. But recent developments in the miniaturisation of X-ray analytic instruments offer a new approach.

Portable X-ray fluorescence (PXRF) provides a fast, economical and non-destructive alternative for measuring the elemental composition of a stone artefact or rock sample. Highly successful for compositional 'fingerprinting' of obsidian artefacts, PXRF is now being tested on basalt ground-edge axes collected from eastern NSW over the last century in a pilot study between the Australian Museum and University of New England.

The study aims to match these axes, part of the Australian Museum's Archaeology collection, with their most likely basalt origins. While it is still early days, good reproducible results are already showing that, despite superficial similarities, axes found in the same region can be quite distinct in their geological composition. The next step is to link these elemental signatures to the source outcrops.

PXRF represents a major technical breakthrough allowing archaeologists and anthropologists to refine our understanding of the complexity and diversity of Indigenous peoples and their cultures.

Dr Val Attenbrow is a Principal Research Scientist, Anthropology at the Australian Museum. Dr Peter Grave is Convenor of Archaeology at the University of New England, Armidale.

Further reading:

Binns, RA and McBryde, I, 1972. A petrological analysis of ground-edge artefacts from Northern New South Wales. Australian Institute of Aboriginal Studies, Canberra, ACT.

McCarthy, FD, 1939. 'Trade' in Aboriginal Australia, and 'trade' relationships with Torres Strait, New Guinea and Malaya. Oceania 9: 405-38, 10: 80-104, 171-95.