Rock art paintings in Jawoyn country, Arnhem land: how improve knowledge

PosterWestern Arnhem Land's rock art is world famous yet very poorly dated. Understanding its history over tens of thousands of years has huge implications for understanding Aboriginal cultural history. In this purpose, the rock art of the Arnhem Land plateau of Jawoyn country is archaeologically characterized and dated (1). Within the framework of "Jawoyn Rock Art and Heritage Program", this study focus on one particular rockshelter, where a bird, extincted 45 000 years ago, the Genyornis Newtoni was represented (2). During the excavation, pieces of colored matter were considered as potential pigment. In order to determine, i) the nature of used pigments constituents and their preparation mode, (ii) their geographic origin and (iii) the chronology of paintings, rock-painting pigments were sampled on the Genyornis panel and compared with excavated samples. Macroscopic observations (MO), thus analysis of the pigments composition carried out by means of scanning electron microscopy coupled to an energy-dispersive X-ray spectrometer (SEM-EDS) and microspectroscopy Raman have been used. Iron oxides, in the form of hematite and goethite, have been identified on the paint layer. The white matrix, rich in silicon, has been identified as a weathering rock bottom layer, whose origin still remains unknown to this time. Presence of various crustings and bottom has been confirmed for some samples. Finally, the unexpected presence of phosphorus, in relatively high rates on the samples surface, can be linked to the nature of chemical components present in bombs used to launch the famous Australians bushfires. Through this first study on the characterization of the Jawoyn Rock Art, we try to improve the understanding of the interaction between pigment and rock support in order to evaluate the vulnerability of this rock art. Reconstructing the chronology of the various figures is steel a big challenge involving accurate observation and well resolved analysis and an estimation of the erosion effect of this outdoor site