New Tools and Old Stones: The Use of 3D Microscopy on Stone Tools to Understand Prehistoric Behaviour and Social Change

Common questions asked by the public of stone tools are 'what were they used for?' or, of the people, 'what were they doing there?' The primary aim of this project is to develop and demonstrate a technique that allows these questions to be reliably answered and illustrated.

This project presents the analysis of an archaeological assemblage as a case study, designed to introduce new methods of high resolution three dimensional laser scanning microscopes to study archaeological stone tools. This presents the integration of methods from engineering into the study of heritage to improve the quality of archaeological research by digital transformation of current approaches.

Lithic microwear analysis is a technique that has been developed to study stone tool use. It involves the use of microscopes to study edges of stone tools to find areas that have been worn through use. This method has allowed archaeologists to gain insight into prehistoric activities but there are known flaws which experts aim to improve. The main problem is the method relies on visual discrimination of surface wear. Testing of the method shows that this qualitative assessment of tool function is highly inaccurate and inconsistent.

Stone tools are the primary artefact left by our ancestors as they have evolved over the last 4.5 million years. An understanding of stone tools is therefore fundamental to understanding evolution and social change. An important aspect of stone tool analysis is understanding how they were used. This level of understanding can help up learn about social development, environmental adaptation through climate change, and technological specialisation.

The assemblage studied is an Upper Palaeolithic set of stone tools from the site of Wey Manor Farm, a well preserved site from surrey. It represents one of only a few discovered in the UK that show a good degree of preservation and was meticulously excavated, presenting a unique opportunity to match data from the location of tools at the site and activities carried out by their prehistoric users. The good preservation of the assemblage makes it highly suitable for the project as the ability to gather useful data from the tools and high quality graphics illustrating a variety of different tool uses will serve to highlight the capabilities of the approach used.

The new technology introduced by this project aims to transform the approaches used through the addition of quantitative analysis wear and computed interpretation. The method changes the way that archaeological data is visualised and allows a shift of focus from method to interpretation.

The visualisation of data in this new way reduces the complexity of the interpretative problem. Experts will no longer needs to visually discern complex and often subtle textural information. The task of textural characterisation is taken up by the computing system as is the interpretation of what this implies for tool use. This reduces error in identification, improves consistency, and strengthens the reputation of the method as a whole. This allows the expert to shift focus to the interpretation of results and the implications of these in the broader context of the archaeological question at hand.

The reduction in need for the expert to be familiar with the visual system of remembering and cataloguing worn surface types for the purpose of future analysis also dramatically reduces the requirement for the associated extensive training (4-8 years is currently considered normal). Training requirements to use this new system will be on the scale of months; closer in line to other analytical systems in use across the applied sciences. This will make the technique more accessible across the discipline; a compound effect being the production of larger datasets pertaining to site function and subsequently a greater base for interpretation of heritage.

Heritage practitioners and curators will have immediate benefit through hands on learning and knowledge transfer as a result of attending the project workshop. Small bursaries will be offered to increase the range of those able to attend. The workshop combines a series of short lectures and demonstration of equipment and documentation. There will be a better understanding of the potential for the use of microwear analysis and advanced methods and the ways to present this data to a broader audience.

The project outputs are aimed at practitioners outside of academia such as curators, object handlers and excavators. The consequence of this will be a better understanding of the value of microwear analysis across archaeology as an interpretive tool. This crosses over to a gained understanding of the problems of post-excavation damage and suitable handling methods to ensure optimal preservation of material for study. This will improve communication between curators, heritage specialists, and researchers about the best practices for conservation and analysis of material to study site activities and function.

1) The method under investigation is capable of producing images of high quality that illustrate wear from tool use on early prehistoric implements. The effect of visualising this allows data to be communicated to a wide audience. This presents opportunities for museums to display high quality images of tool wear in a way that is useful for public engagement. The nature of these images means that they can be appreciated as they are. Direct observation of wear is the only current way to adequately showcase its features to the public, this situation changes with the presentation of the high resolution, high depth images produced by laser scanning systems. The surfaces can be visualised as a sort of 3D landscape and displayed in interactive systems, moving beyond a simple digital photograph. This extends to the media whereby the quality of the output from such systems is far more suitable for the needs of print.

2) The quality of data. High quality data in archaeology leads to high quality interpretations and a better understanding of the archaeological record and, in this case early prehistoric archaeology. The impact to society is that the research forms the basis of good method that has the onward impact of producing a quality interpretation and presentation of heritage, early prehistoric life, and human evolution to the public.