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Understanding wear from the workshop on “Residues and Hafting”. University of Liege (Belgium), 2-4 June 2015.

Tuesday, 2 June, 2015 to Thursday, 4 June, 2015
Linda Hurcombe
Alice La Porta
Number of Participants / Visitors / Audience: 
1 particpant

Alice La Porta attended the workshop on behalf of the Exeter usewear group and gives the following report as part of our Openarch actions on usewear and the function of tools..

The Workshop chaired by Dr. Veerle Rots has been organized by the TraceoLab research team, specialized on use-wear and residues analysis. During the three days, oral presentations have been alternated with practical microscope observations. Considerations about methods and techniques applied on use-wear and residues analysis and the role of experimental archaeology on the replication of wears were the main topics. More than 25 attendees came from Belgium, France, Netherland, England, Italy, Finland, Germany, Portugal, and Australia, both from university departments or independent museums.
The three days workshop (2-4 June 2015) has been a crucial moment for understanding the interdisciplinary possibilities offered by archaeological sciences. Professors, researchers and PhD students presentations have covered several topics about the current state of use-wear/residues analysis and the several disciplines related to it. The last day instead was dedicated to practical microscope observations, exhibition of experimental projects and applied exercise of residues extractions.
One of the main topics of the conference largely addressed methods and issues related with residues analysis. Many residues can still be found on the archaeological artefacts due to utilization, hafting, manufactures, or contamination. The issue of contamination (residues that come from the surrounding environment) is apparently affecting many researches and many questions have been devoted to this subject. Different approaches using reflected microscope light (as on the African artefact examination) and transmitted microscope light (as applied by European or American analysts) are possible. Extraction techniques for obtain the large amount of residues from the artefacts are mainly two: pipette extraction and ultrasonic bath. Both of them, it has been underlined, cause problem of damage of residue or development of mold and bacterial attacks. From the discussion has emerged that quantitative problems, concerning A. how many residues has to be found onto a tool surface and B. how many tools on the data-set have to show residue-remains to allow a punctual interpretation, are the most. A shared conclusive opinion was that residues analysis have to be correlated with use-wear analysis and they have to rely on analogies with solid referential collections, as well as on a percentage of minimum number residues present onto a tool. Online resources such as the online database for residues of University of Missouri have also been presented.
Adhesives were also covered as a topic of importance. Which adhesives have been used in Prehistory? How many types? How it is possible to chemically track their residues? were the most frequently questions. Adhesives seems to have been used since Early Palaeolithic and beyond for hafting, isolation, pigments, etc. The use of those adhesives can leave traces and residues onto the tool surface, which can be divided in: organic residues (glues, tars and gums) and inorganic residues (minerals such as ochre). Different methods destructive (DI-MS spectrometry, chromatography) and not destructive (Raman Spectroscopy, SEM-EDX) were presented in order to trace the chemical spectrum of adhesive residues and to recognize organic from inorganic residues. During the debate, has been pointed out the importance of using adhesive residues from archaeological findings and comparing them with experimental archaeology reproductions to test the efficiency and the performance of different adhesive (birch bark tar, pine resin, beeswax and animal glues).
Hafting phenomena is was probably the main topic of the conference. Professor Lawrence Barham has presented anthropological, cognitive and technical innovations related to the discovery of hafting. It was interesting to remark the difference between innovation and invention concepts, and how one is related to the other. The essential notion of combinatorial technology has been also clarify to identify how and when the hafting revolution took place. Further presentations have pointed out the methods to decode hafting traces from archaeological tool, using both techno-functional and experimental approaches. Experimental programmes conducted on reproduction of hafted throwing weapons were also presented. During the discussion issues connected with different hafting systems and their efficiency have been debated presenting results from experimental works.
A key part of the workshop was the relation between use-wear analysis and experimental archaeology. The role played by experimental archaeology on the replications of ancient behaviours, gesture and technological productions is inescapable. Without experimental referential collections use-wear and residues analysis would be impossible to perform. The analogies between archaeological (past) wears and experimental (actualistic) wears is the base of the this discipline. Then, the contribution of several set-experiments related to use-wears (weapon trials, reproduction of hafting tools, and replication of ancient adhesives) has emphasized that experimental archaeology has to be connected with archaeological problematic in order to be considered scientific and not mere crafts (which it might become the case in the next future).
The conference ended with the realization of microscopic observations of experimental referential collections of hafted, use-related tools (polish, residues and impact fractures). During the lunch break a new experimental protocol related to throwing and weaponry experiments has been presented with a 3D, full size mold of a horse reproduction which will be used as a target during weaponry trials (ongoing PhD project at Liege University).
The importance of this symposium lies on the dialogue between several archaeological branches, such as cognitive archaeology, experimental archaeology, chemical studies and use-wear studies. It was evident at the end of the conference how use-wear and residues analysis, after more than thirty year of criticisms, is nowadays a consolidated and validated disciplines which is becoming essential on lithic studies and techno-functional interpretations. More and more lithic technologists (which before were sceptical) are now approaching use-wear analysis in a more concrete way, reshaping research questions and scientific problematic in an experimental and functional optic.