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Science: Ancient artists painted with human blood

Science: Ancient artists painted with human blood

作者:尤旯毹  时间:2019-02-26 07:15:00  人气:

By SARAH BUNNEY PREHISTORIC people in Australia and Tasmania used human blood as the red pigment in their rock paintings. Scientists have detected protein from human blood in motifs at two sites in Australia: Laurie Creek in the northwest of Northern Territory and Judds Cavern in southwestern Tasmania. The cavern is one of the longest river caves known in either Australia or Tasmania. The motifs in Laurie Creek were painted about 20 000 years ago, and the Tasmanian ones between 10 000 and 11 000 years ago. Thomas Loy, Rhys Jones and their colleagues at the Australian National University in Canberra collaborated with a Canadian team from Simon Fraser University at Burnaby, British Columbia. The researchers took tiny fragments of the pigmented layers that were flaking off the rock walls. They used a technique known as accelerator mass spectroscopy to obtain radiocarbon dates for the organic matter in the residues (Antiquity, vol 64, p 110). Rock art is difficult to date. Usually, when archaeologists look at paintings or engravings that are more than 10 000 years old, they have to use indirect methods of fixing the date. This means that they must investigate the surface covering of the motif, or stone tools or other human debris at the site, rather than the art itself. For example, they can obtain clues to the age from the depth of the mineral varnish it has accumulated. However, such indirect methods give only a very approximate date for a piece of art. The dates obtained by Loy and his colleagues are interesting because they are direct measurements, obtained from the art itself. They are also interesting because they document an ancient, possibly ritualistic, use of human blood. There is ethnographic evidence that human blood has been used in ritual ceremonies in Australia and New Guinea in modern times. For this reason, when the art at Laurie Creek and Judds Cavern was discovered in 1987, Australian archaeologists decided to examine the red pigments for blood residues. The archaeologists applied immunological methods pioneered in the early 1980s by Loy, who was then working in Canada. Loy has found that blood residues can survive for tens of thousands of years. Previously, he has studied the surfaces of ancient stone tools and managed to identify proteins from mammalian blood. The panels of red pigment at Laurie Creek are superimposed on engraved decorations, presumably the work of even earlier artists. Even until modern times, rock artists favoured the creek’s rock shelters. In Judds Cavern, the paintings consist of groups of hand stencils, and panels smeared with red pigment. Most of the motifs are high up on the walls, about 35 metres from the cave’s entrance, where daylight does not penetrate. Since the discovery of Judds Cavern, archaeologists have found two other caves in the same area of Tasmania with similar motifs. These have yet to be dated. There is good archaeological evidence that people occupied caves in this part of Tasmania from about 20 000 years ago. They continued to live there until sometime between 13 000 and 11 000 years ago. The final phase of occupation tallies well with the radiocarbon dates for Judds Cavern. Tasmania was colonised at least 30 000 years ago by people who had travelled from mainland Australia. A land bridge existed intermittently there during the latest ice age. Although there is no evidence of rock art as early as this in Tasmania, there is on the mainland. Indirect evidence of such art comes from the patina of ‘desert varnish’ on rock engravings in South Australia (New Scientist, Science, 15 April 1989). Robert Dorn of Arizona State University and his colleagues have dated these ‘pecked’ motifs and believe that some of them may be up to 31 000 years old,