Blood of the Red Kangaroo: Weld Range Ochre Geochemistry | Other
Blood of the Red Kangaroo: Weld Range Ochre Geochemistry
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24.01.2022 After some technical issues sharing video files with the Weld Range Wajarri traditional owners, we can now bring you video with sub-title notes to showcase the ochre testing we did late last year. This first video is of Wajarri traditional owner, Colin Hamlett, explaining some of the significance of the nationally heritage listed Weld Range ochre mines. The video has been approved for public viewing by Weld Range Wajarri traditional owners. Australian Geographic The University of Western Australia UWA Research
24.01.2022 Good afternoon - here's some more rock art science from Weld Range for you! Within Source Variation The primary aim of this project was to describe compositional variation within and between two Aboriginal ochre mines located in the same geological unit (Wilgie Mia and Little Wilgie). We then went on to compare these descriptions to the composition of local Aboriginal sites containing pigment as rock art and surface finds. The two graphs here show multivariate statistical a...nalyses of 33 light elements measured by pXRF at Wilgie Mia, Little Wilgie, and two rock art sites, Stickman Rockshelter and Genealogy Rockshelter. The first graph shows a Principle Component Analysis (PCA) and the second graph shows a Hierarchical Cluster Analysis (HCA). In the PCA graph (the one that looks like a cube), readings from Wilgie Mia are represented by circles whilst readings from Little Wilgie are represented by squares. Readings from the rock art sites are either open triangles for Stickman Rockshelter or filled-in triangles for Genealogy Rockshelter. The PCA analysis shows some separate clusters for readings taken at Wilgie Mia and Little Wilgie respectively, but also a lot of overlap with data points from both ochre mines clustering in the middle of the graph. Readings taken at both rock art sites lie within the green dashed line with three of the Little Wilgie data points and one from Wilgie Mia. In the HCA graph (the branching,curly one), points 45 and 46 within the green dashed circle represent two readings from Little Wilgie which cluster on the same branch as readings from the rock art motifs and the natural rock surfaces within the rock art sites. This is interpreted as broadly supporting an earlier chemical study of rock art at Weld Range. The previous project used LA-ICP-MS, a very sensitive laboratory technique which takes readings of trace element make-up. This work found that most of the rock art at two other Weld Range rockshelters could have been made using ochre from Little Wilgie but probably not ochre from Wilgie Mia. Again, in our Blood of the Red Kangaroo project, we have found that pXRF analysis matches rock art more closely with pigment from Little Wilgie than it does with Wilgie Mia. However, the fact that natural surfaces at the rock art sites also cluster with readings from rock art and Little Wilgie may indicate that natural processes of weathering (more pronounced at Little Wilgie than within the cave of Wilgie Mia) may be affecting things. Graphs Legend: Soil parameters assays (corrected for LOD and error) measuring: S, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Zr, Mo, Pd, Ag, Cd, SN, Sb, Te, Cs, Ba, W, Au, Hg, Pd, Th and U. 3D scatter plot of PCA 1-3 (correlation matrix) (right) and constellation plot of (Wards) hierarchical cluster analyses (left). Circles = Wilgie Mia, Squares= Little Wilgie, Triangles = rock art (SM = open, GS = solid). Colours are the same in both graphs. See more
20.01.2022 To find out more about how ochre was used by Wajarri ancestor’s at Weld Range in the past, we analysed rock art at the ‘Stickman’ and the ‘Genealogy’ rockshelter sites using non-destructive and non-invasive VNIR-SWIR spectroscopy. The pink line in the graph posted here shows the result from a painting at the Genealogy site that is understood by Weld Range Wajarri to relate an event recorded by Daisy Bates in the early 1900s (Bates 4 Dec 1909). The mostly blue line shows a rea...ding of red ochre for comparison with the pink line. If you look at the numbers along the bottom of the graph they go from below 400 on the left hand side to above 2400 on the right hand side. Red ochre shows up as dips in the readings for wavelengths below 1000 nm on the left. The clay content shows as dips or ‘features’ at wavelengths above 1000 nm on the right. The pink line matches the mostly blue line below 1000 nm. Above 1000 nm the blue line is mostly flat contrasting with the many dips in the pink line. The vertical lines on the graph mark the features of pure kaolinite which match well with the dips in the pink line. We can conclude from the pink line that the painting at the Genealogy site includes both red ochre (hematite) and clay that is kaolinitic. A reading taken of the natural clay wall on which the image was painted showed a clay that was different from the clay in the painting (halloysitic rather than kaolinitic). Kaolinite is also known as pipe or China clay and has special adhesive powers when used in paints. Whether the Wajarri ancestors used kaolinite as a binder or for another purpose, or whether the clay was incorporated naturally has yet to be discovered, but VNIR-SWIR spectroscopy as shown here gives rare insight into the make-up of paints used by yamaji (that’s the Wajarri word for ‘man’ or ‘Aboriginal people of the Mid West’) one hundred years ago and may give researchers clues about paint-making traditions from further back in time. Bates, D. 4 Dec 1909 The death of Booreangoo: An Aboriginal burial. Western Mail.
19.01.2022 In this short video, Erick Ramanaidou from CSIRO discusses some preliminary results of non-destructive near infrared spectroscopy (VNIR-SWIR) readings on ochre at Weld Range sites. He asks whether the ancestors of the Wajarri Traditional Owners may have added the clay mineral 'kaolinite' to ochre to make paint? This is a question of great interest to Karen Horn, seen on the right in the video, who has been researching ochre paint recipes.
15.01.2022 The Aboriginal ochre mines of Little Wilgie and Wilgie Mia at Weld Range are really important cultural sites. The Wajarri Yamaji story of their creation has been written down several times with some small differences between versions this one was recorded in an American journal:"Two miles southwest of Wilgamia is a hill known as Little Wilgie. Smaller in size and wealth of ochre it is nevertheless more important mythologically. Typical of the dramatizations associated with... natural features of the terrain in much of the continent is the story of how a kangaroo, in mythical times, was speared about six miles south of Wilgamia. In his death agony he jumped and landed at Wilgamia where the red represents his blood, the yellow his liver, and the green his gall. His last leap brought him to Little Wilgie which marks his grave. According to the story Little Wilgie was discovered before Wilgamia Quote from Davidson, D.S., 1952. Notes on the pictographs and petroglyphs of Western Australia and a discussion of their affinities with appearances elsewhere on the continent. Proceedings of the American Philosophical Society, Volume 96, page 82, Footnote 4. See more
13.01.2022 In our next two posts we are showcasing the two different techniques that we will be testing on ochre from Wilgie Mia and Little Wilgie. First up, CSIRO scientist, Dr Erick Ramanaidou tells us how VNIR works: Visible - Near Infrared (VNIR) spectroscopy is a technique that records reflected light in the visible and near infrared range from the surface of materials. The VNIR instrument shows the results as a line, or spectrum, which moves from low wavelengths on the left to hi...gh wavelengths on the right. The line goes higher when minerals reflect light and lower when light is absorbed. Different minerals have distinct absorption features at specific wavelengths. For example, minerals like kaolinite have strong absorption features at 1400 and 21002450 nm. VNIR is a good technique to use on cultural material because it can be used at places in the landscape (not just in the laboratory), there is no need to take or destroy samples and it doesnt cost a lot of money to take the readings. VNIR can also identify plant and animal substances which have been mixed with ochre to make paints used in art. VNIR has great potential in archaeological research and has been used to identify the source material in an object, detect art forgeries and even estimate the age of engraved art. (First image shows Viv Brown, Brendan Hamlett, Liam Bell and Erick Ramanaidou with the NIR instrument at CSIRO. Second image shows examples of NIR spectra published by Erick and colleagues in 2015) See more
10.01.2022 So far, our investigations of ochre chemistry have led us to question whether white kaolinite clay may have been purposely added to ochre by Wajarri ancestors to make the paints used in Weld Range rock art. In our post on 13th March, Erick Ramanaidou (CSIRO) observed that the kaolinite peak measured by VNIR-SWIR in some Wajarri rock art was larger than the kaolinite peaks measured in the main Wilgie Mia and Little Wilgie ochre mine sites. Our post on 11th May, based on work ...by Karen Horn (UWA research student 2016), suggested differences between the clay content of analysed rock art compared with both ochre from the ochre mines and the natural rock underneath the paintings. To further test this idea, we examined clay proxies in complementary pXRF readings, specifically the titanium and potassium peaks. Clays are aluminosilicate minerals and very light elements like aluminium and silicon are below the detection limits of the instrument we used. However, white rock art pigments made from clays throughout Australia have been found to contain micas, especially muscovite, which contains potassium. pXRF analyses indicates that clays are a component of both the ochre sources and the rock art. Whereas calcium measured in rock art motifs correlated strongly with the composition of the underlying natural rock wall. Also that mica clay marked by the potassium content appears to be a major constituent in both ochre quarries as well as the rock art. Clays are concentrated in mineral horizons in the landscape, including within the ochre mines seen Figure 3 top left as the thick white vertical line in the rock face behind the European mine workings at Little Wilgie (it was not possible to analyse this seam because it is on the back wall above a vertical shaft). The breakaway cliffs in which rock art sites are located (Stickman, Figure 3 top right and Genealogy Figure 3 bottom) are themselves dominated by kaolinite clay. The pXRF evidence suggests that the clays in Weld Range rock art might have been already mixed up with the ochre when it was quarried from the source. Since minerals dissolve or disperse in water, clays might also have redeposited onto the surface of the rock art in the time since the paintings were made. See more
09.01.2022 Now that we know how VNIR differentiates between materials (i.e. various minerals and organic compounds), here is a post from Dr Jillian Huntley at Griffith University about pXRF. Portable X-Ray Fluorescence (pXRF) has been around for over 40 years. About the size of a cordless drill, these 'ray-guns' measure different chemical elements. The pXRF can't measure all the elements in a sample, but measures most from silicon to uranium on the periodic table see the second pictu...re posted here which highlights the elements that can be measured by pXRF. As the name suggests pXRF is field portable and can be applied to sites directly - there is no need to take a sample back to a laboratory. Pigments (including ochre), rock art and the natural rock around it can be measured using pXRF which helps us to understand better the cultural landscapes and technologies of artists in the past. The results of pXRF appear on a screen when the measurement is taken so we can investigate interesting readings right there in the field, rather than having to wait for a laboratory report to find out the results. Like VNIR, pXRF is also cost effective once youve bought the ray-gun there are few ongoing costs beyond recharging the batteries and occasionally replacing the thin film protection over the snout. This means researchers can collect a lot of data, relatively quickly, in the field. Images: 1) Jillian Huntley taking pXRF readings in the field 2) the periodic table of elements with the ones pXRF can detect highlighted in yellow with a red outline 3) an example of pXRF data. See more
08.01.2022 WELCOME! Following on from the hugely successful federally funded @WeldRangeWebOfKnowledge, Weld Range Wajarri and collaborators at UWA, CSIRO and Griffith University are excited to announce our newest project, partly funded by the Australian Geographic Society http://www.australiangeographic.com.au/society and partly funded by the participating institutions, companies and individuals. Building on successful geochemical analysis which managed to distinguish between the ochre ...from Little Wilgie and Wilgie Mia by using the rather expensive technique of Laser Ablation-Inductively Coupled-Mass Spectrometry, the Blood of the Red Kangaroo Project aims to assess whether portable X-ray Fluorescence (pXRF) and Visible and Near Infra-Red (VNIR) techniques can usefully describe the chemistry of ochre from Wilgie Mia and Little Wilgie and perhaps also determine unique chemical features which relate to either one or the other mine. This information could then be used to test ochre at distant heritage places or on museum artefacts and track the past use of Weld Range ochre across space and back through time! Sound interesting? Like our page and follow our progress here - we'll explain the whys, whats and hows of the project and keep you up-to-date with results as they come in. See more
07.01.2022 In this video, archaeological scientist, Dr Jillian Huntley from Griffith University, explains how readings from the portable x-ray fluorescence (pXRF) instrument are calibrated.
07.01.2022 Warning - this video shows the inside of Thuwarri Thaa / Wilgie Mia. The video is posted here with the permission of the Weld Range Wajarri Traditional Owners. How easy is it to take VNIR readings in the field? Very Near Infrared spectroscopy readings are taken very quickly and the instrument is highly portable - here it is carried in a backpack. In this video Carl Hamlett operates the 'gun' whilst Brendan Hamlett receives the readings on the laptop. CSIRO's Erick Ramanaidou indicates locations to take measurements and five readings are taken at the same spot to check that the readings are repeatable and to manage errors. Great teamwork guys.
05.01.2022 To find out more about how ochre was used by Wajarri ancestors at Weld Range in the past, we analysed rock art at the Stickman and the Genealogy rockshelter sites using non-destructive and non-invasive VNIR-SWIR spectroscopy. The pink line in the graph posted here shows the result from a painting at the Genealogy site that is understood by Weld Range Wajarri to relate an event recorded by Daisy Bates in the early 1900s (Bates 4 Dec 1909). The mostly blue line shows a rea...ding of red ochre for comparison with the pink line. If you look at the numbers along the bottom of the graph they go from below 400 on the left hand side to above 2400 on the right hand side. Red ochre shows up as dips in the readings for wavelengths below 1000 nm on the left. The clay content shows as dips or features at wavelengths above 1000 nm on the right. The pink line matches the mostly blue line below 1000 nm. Above 1000 nm the blue line is mostly flat contrasting with the many dips in the pink line. The vertical lines on the graph mark the features of pure kaolinite which match well with the dips in the pink line. We can conclude from the pink line that the painting at the Genealogy site includes both red ochre (hematite) and clay that is kaolinitic. A reading taken of the natural clay wall on which the image was painted showed a clay that was different from the clay in the painting (halloysitic rather than kaolinitic). Kaolinite is also known as pipe or China clay and has special adhesive powers when used in paints. Whether the Wajarri ancestors used kaolinite as a binder or for another purpose, or whether the clay was incorporated naturally has yet to be discovered, but VNIR-SWIR spectroscopy as shown here gives rare insight into the make-up of paints used by yamaji (thats the Wajarri word for man or Aboriginal people of the Mid West) one hundred years ago and may give researchers clues about paint-making traditions from further back in time. Bates, D. 4 Dec 1909 The death of Booreangoo: An Aboriginal burial. Western Mail.
01.01.2022 Before doing the Blood of the Red kangaroo fieldwork, the researchers needed to make sure they had all the right government permissions in place. To do non-destructive VNIR and pXRF the team needed permission under Regulation 10 of the Aboriginal Heritage Act 1972 to enter the protected area of Wilgie Mia. The researchers also needed permission to enter the Aboriginal Reserve of Wilgie Mia. It is only possible for researchers to work at Weld Range in close collaboration wit...h the Wajarri Yamaji Traditional Owners of Weld Range. The area isn't open for general public access. On behalf of the Blood of the Red Kangaroo project researchers from UWA, CSIRO and Griffith University - thank you to the Weld Range Wajarri Yamaji for hosting this fieldwork. Next up...outlines of the testing undertaken and some preliminary thoughts on the results... See more
