Ochre

Throughout this semester I have been working with industry partner Dr Lynley Wallis, principal archaeologist with Wallis Heritage Consulting (WHC) as part of a cultural heritage practicum. During my placement with WHC I’ve performed myriad duties ranging from general business, logistical and administrative tasks, to gaining experience in writing and submitting grant applications, and the preliminary analysis of ochre samples.

By far the greatest extension of my knowledge has come from working with ochre samples collected from the Gledswood Shelter 1 (GS1) site, northwest Queensland. Having no past experience with ochre, (other than having possibly read a paper that mentioned ochre in passing) I have been madly reading in an effort to understand the importance of ochre in the archaeological record, preservation factors, chemical structure, provenancing and known trade routes. I have also been comparing the uses, benefits and shortfalls of current analytical techniques such as neutron activation analysis (NAA), particle induced x-ray emission (PIXE), X-ray fluorescence (XRF), X-ray diffraction (XRD) and laser-induced breakdown spectroscopy (LIBS).

My initial task was to complete a preliminary sort of the GS1 ochre, and then to count, weigh and re-bag the ochre by spit. I’m currently in the process of sorting the ochres into groups based on colour. At this stage there are three dominant colour groupings: red, weak red and yellow.

Ochre

Figure 1 Ochre samples from GS1

Next, following Smith and Fankhauser (2009), I’ll sort these groupings further by their appearance (such as waxy, metallic or greasy), and by texture (friable/talcy or hard).

Already it’s apparent that many of the ochre pieces show evidence of use with clearly identifiable striations from grinding, which I’ll be examining further with low power microscopy and then photographing. Stay tuned for my next update on this exciting research!

References

Smith, M. and B. Fankhauser 2009 Geochemistry and Identification of Australian Red Ochre Deposits. Paleoworks Technical Papers 9. Canberra: National Museum of Australia and Centre for Archaeological Research.

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