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- Evaluating the microscopic effect of brushing stone tools as a cleaning procedurePublication . Pedergnana, Antonella; Calandra, Ivan; Bob, Konstantin; Gneisinger, Walter; Paixão, Eduardo; Schunk, Lisa; Hildebrandt, Andreas; Marreiros, JoaoCleaning stone tool surfaces is a common procedure in lithic studies. The first step widely applied at any archeological site (and/or at field laboratories) is the gross removal of sediment from the surfaces of artifacts. Lithic surface alterations due to mechanical action applied in wet or dry cleaning regimes have never been examined at a microscopic scale. This could have important implications in traceology, as any modern surface modifications inflicted on archeological artifacts might compromise their functional interpretations. The current trend toward quantification of use-wear traces makes the testing even more important, as even slight, apparently invisible surface alterations might be measured. In order to evaluate the impact of common cleaning procedures, we undertook a controlled experiment. The main aim of this experiment was to assess the effects that brushing actions applied for removing sediment particles have on flint and quartzite surfaces. All surfaces were analyzed with confocal microscopy before and after having been brushed to quantify possible changes in the micro-topography. Surface roughness parameters (ISO 25178-2 among others) were applied. Nine parameters changed significantly when mechanical actions were applied to lithic surfaces, meaning that some changes in the surface micro-topography were detected. Therefore, archeologists need to be cautious when applying prolonged mechanical actions for cleaning archeological stone tools.
- Back to the edge: relative coordinate system for use-wear analysisPublication . Calandra, Ivan; Schunk, Lisa; Rodriguez, Alice; Gneisinger, Walter; Pedergnana, Antonella; Paixao, Eduardo; Pereira, Telmo; Iovita, Radu; Marreiros, JoaoUse-wear studies rely heavily on experiments and reference collections to infer the function of archeological artifacts. Sequential experiments, in particular, are necessary to understand how use-wear develops. Consequently, it is crucial to analyze the same location on the tool's surface during the course of an experiment. Being able to relocate the area of interest on a sample is also essential for reproducibility in use-wear studies. However, visual relocation has limited applicability and there is currently no easy and efficient alternative. Here we propose a simple protocol to create a coordinate system directly on the sample. Three ceramic beads that serve as reference markers are adhered onto the sample, either with epoxy resin or acrylic polymer. The former is easier to work with but the latter is reversible so it can be applied to archeological samples too. The microscope's software then relocates the position(s) of interest. We demonstrate the feasibility of this approach and measure its repeatability by imaging the same position on an experimental flint blade 10 times with two confocal microscopes. Our results show that the position can be relocated automatically with a horizontal positional repeatability of approximately 14% of the field of view. Quantitative surface texture measurements according to ISO 25178 vary due to this positional inaccuracy, but it is still unknown whether this variation would mask functional differences. Although still perfectible, we argue that this protocol represents an important step toward repeatability and reproducibility in experimental archeology, especially in use-wear studies.
- Why should traceology learn from dental microwear, and vice-versa?Publication . Calandra, Ivan; Pedergnana, Antonella; Gneisinger, Walter; Marreiros, JoaoDental and artifact microwear analyses have a lot in common regarding the questions they address, their developmental history and their issues. However, few paleontologists and archeologists are aware of this, and even those who are, do not take into account most of the methodological insights from the other field. In this focus article, we briefly review the main developmental steps of both methods, highlight how similar their histories are and how combining methodological developments can improve both research fields. In both cases, the traditional analyses have been strongly criticized mainly because of their subjectivity and their lack of repeatability and reproducibility. Quantitative surface texture analyses have been proposed in response, resulting in dental microwear texture analysis (DMTA) and quantitative artifact microwear analysis (QAMA). DMTA is however a more mature method than QAMA and is well supported within the paleontological community. In this paper, focused on the methodological framework of both fields, we address this topic by arguing that traceologists could borrow a lot from DMTA; this would allow QAMA to become an established method much more quickly. Dental microwear analysts can also learn from traceology, especially regarding sample preparation, experimentation and residue analysis. We hope that this focus article will stimulate more awareness, exchange and collaboration between paleontologists and archeologists, and especially between dental and artifact microwear analysts. Paleontology, archeology and the field of surface analysis as a whole would all benefit from such cooperation.
- A ‘family of wear’: traceological patterns on pebbles used for burnishing pots and processing other plastic mineral mattersPublication . Dubreuil, Laure; Robitaille, Jérôme; Gonzalez-Urquijo, Jesús; Marreiros, Joao; Stroulia, AnnaThe development of technologies related to plastic mineral matters (PMM), including clay, mud, and plaster, represents a major step in cultural evolution because of their important repercussions for food processing, storage, transportation, construction, and symbolic expression in past human societies. This paper aims to illuminate the chaines operatoires employed in the transformation of PMM and highlight early evidence for these technologies in the archaeological record. Our focus is 'ad-hoc' (or non-manufactured) ground stone tools used in finishing operations. Specifically, we discuss pebbles and cobbles employed to regularize, smooth, or burnish clay and mud-based products. Because these tools consist of unmodified rocks, recognizing and understanding the traces developed through use is essential for their identification. This is a pilot study that draws on experiments, ethnographic studies and quantification via confocal microscopy to assess the variability of use-wear developed on mud and clay processors. Extra attention is placed on micro-polish, not only because this type of wear has been seldom described before for such tools, but also because it appears to be highly diagnostic. We suggest that the variability observed can be described as a family of wear, that is, a range of recurrent use-wear characteristics associated with the processing of PMM. We analyze two collections associated with different chrono-cultural contexts: the Late Natufian site of Hilazon Tachtit in the Southern Levant and the Late Neolithic site of Kremasti-Kilada in Greece. At both sites, the identification of processors of PMM provides pivotal data to understand the relevant chaines operatoires, assess the emergence and development of these technologies, and also explore symbolic behaviors.