Our previous research in the Tankwa Karoo took place within the framework of my PhD. This mapped surface artefacts through surveys to understand how people’s landscape- and tool-use varied across space and through time, over the past million years. As part of this, we dedicated 12 days to collecting information on artefacts at Tweefontein which, together with new data and approaches, will be central to the TANKwA project.
In 2015, Matthew Shaw and I carried out an attribute-based analysis of a sample of the artefacts at Tweefontein. This involved recording the individual features (attributes) of cores, points and other artefacts and taking precise measurements of various dimensions. A key aim was to ask whether what we thought looked like Nubian technology fitted with a thorough technological definition of it. To do this, we used a set of attributes set out by Vitaly Usik and colleagues when they asked the same questions of their Nubian-like artefacts in Arabia.
We were able to confirm that our sample of 121 cores follow coherent patterns, and these fit with features used elsewhere to define Nubian technology. You can read our article on these findings, published open-access in the journal PLoS ONE.
A new approach
An attribute-based analysis is advantageous in many ways as it provides a scientific way of comparing artefacts within an assemblage (at one site), and between different assemblages (at other sites), using the same classification system and measurements. However, certain important characteristics of an artefact are not captured very well in this method – particularly, shape. Rather than simply describing a shape, new digital methods allow us to easily quantify and compare shapes using a technique called geometric morphometrics.
Geometric morphometric (GM) analysis is a way of studying shape using Cartesian landmarks (x, y, z co-ordinates of a point in space) and applying certain statistical methods to compare how the geometry (distances, angles, positions) of these shapes vary. It is widely used in the biological sciences for looking at shape variation in cells, bones, teeth, flowers – essentially anything where you are interested in understanding the relationships between shape and size.
Scientists are increasingly using GM in anthropology to study human bones and fossils to answer questions about evolutionary development and variation, and in archaeology to look at objects. Specific software has been developed to apply these methods to archaeological artefacts such as stone tools, with built-in statistics to answer archaeologically-relevant questions. Open-source packages on the coding platform R can also be used.
We are using an Einscan Pro 3D scanner to capture artefacts in 3D and various R packages to study shape variation at Tweefontein and other comparable sites. A major advantage of this method is that it allows us to leave the artefacts exactly where we found them in the field, and study them from a computer or even print them in 3D.
By combining traditional methods of technological and attribute analysis with innovative 2D and 3D GM methods, we will be able to better understand both the Nubian cores and points at Tweefontein, and Levallois point technology in a wider context.
Overall aims of TANKwA
The research objectives of the project are:
- To test the hypothesis that Nubian technology was an adaptive response to arid conditions in southern Africa,
- To establish a methodological protocol for using attribute and 3D data to study Nubian technology and point production,
- To contextualise the technology of Tweefontein within our understanding of the southern African MSA,
- To contextualise technology at Tweefontein within the global framework of Nubian technology.
This project is funded by the EU and runs from 1 June 2020 until 31 May 2022.