What does ‘Nubian’ mean?
In a geographical sense, ‘Nubia’ refers to the region of Northern Sudan and southern Egypt, with the Nubian Desert forming the eastern part of the Sahara between the River Nile and the Red Sea. Much of the history of Nubia is intertwined with that of Ancient Egypt, which you can read more about here and here.
The first major investigation into the Palaeolithic in Nubia took place ahead of the construction of the Aswan High Dam in the 1960s. In this research, certain distinctive types of stone tool technology were identified and noted for being rather different to technology seen elsewhere. Archaeologists used the term ‘Nubian’ due to their find location and described a distinctive technique of Levallois point production.
Rather than the typical ‘unidirectional convergent’ method of point production where both the preparatory removals and the final blow to remove your product come from the proximal (top) end of the core, J. and G. Guichard describe two alternatives seen in their Nubian cores. In the ‘Type 1’ method, the preparation removals come from the distal (bottom) of the core; in the ‘Type 2’ method, the preparation comes from the laterals (sides). The aim of these specific preparation methods is to create a central ridge that guides force through the stone when you strike it to remove your end-product. By using the Type 1 and 2 Nubian methods, you produce a steeper ridge than you can achieve using the unidirectional method.
Why would your core need to have a steep ridge? It might be that a steeper ridge guides the force so that rather than tapering off, the point stays thicker for more of its length. A thicker point is stronger and less likely to break when it is being used. This could be one reason why people developed Nubian Levallois technology, for producing stronger points.
Complex Nubian problems
The discovery of Nubian Levallois technology in more and more geographical locations has led archaeologists to question what this technology actually means in terms of the people who made it. Nubian technology was initially considered to be an integral part of a Middle Stone Age culture described as the ‘Nubian Complex’.
The problem here is that increasingly where researchers found sites with artefacts reflecting Nubian technology, they assigned the people who made them to being part of the Nubian Complex (this would be a bit like assuming that everyone who has an iPhone is part of the same cultural group). As a result, many different sites across North Africa ended up being described as part of the Nubian Complex even though the specific combinations of artefacts at each site were actually very different and sites cover a very wide time span.
In 2011, new research in the Arabian peninsula reported the presence of distinctive Nubian technology at more than 100 sites in central Oman. This is important for two main reasons. Firstly, previous ideas about how human groups expanded into Asia had hypothesised that people followed the coastlines where food resources were more abundant. Instead, most of the new evidence came from about 60 km inland, suggesting that rather than sticking to the coastlines, they ventured further into the interior. In contrast to the barren desert of the landscape today, the environment at the time would have been much wetter with grasslands rich in animals to hunt. Secondly, these sites dated to about 106,000 years ago which, in 2011, was substantially earlier than the expected ‘Out of Africa’ dates. There is now mounting evidence that modern humans first left Africa as far back as 120,000 years ago, although there were several waves of expansion coinciding with wetter periods as the climate changed.
Cultural spread or shared solutions?
The big question that the discovery of Nubian technology in Arabia has prompted is whether the same group of people who were making tools in this way in North Africa took this knowledge with them as they expanded into Arabia. The logical way of testing this would seem to be to ask whether similar technology exists in the space in between North Africa and the southern tip of the Arabian peninsula. Recent research in the Negev Highlands in Israel has indeed shown this, together with more Nubian finds from the centre of Saudi Arabia. But does this necessarily mean that the same group of people migrated with this technology from Africa to Arabia and beyond, via the Levant? In fact, there are other scenarios to explain how shared ideas and innovations arise in different places. There are three main mechanisms for this: dispersal, diffusion and convergence.
Under the first scenario, as discussed above, one group of people disperse into a new (possibly unpopulated?) area, taking their invention with them. As well as the particular invention (in this case, Nubian technology), we would expect to find a similar cultural ‘package’ in both areas, dating to roughly the same time-span.
In the second scenario, rather than the same group of people moving from one area into another, there are two separate populations in each region who have some contact between them. Through the sharing of knowledge or physical objects, a behaviour such as Nubian technology is passed between neighbouring groups. In this case, we would expect to find more differences in material culture between the two groups, even though they may share one or more specific traits.
In this scenario, there is no direct flow of people or ideas. Instead, the same thing is invented independently by two separate populations in response to similar needs or pressures. The classic example of convergent evolution in biology is the development of wings for flight by birds, bats, insects and now-extinct pterosaurs. Each of these independently developed the specialised adaptations to its body required to get airborne and power movement. They had similar motivations arising from their environments for developing flight – to get food, or avoid predators – and they had to overcome similar problems, such as the principles of aerodynamics.
In cultural terms, there are many examples of times where people have independently invented the same thing: for example, building pyramids in Ancient Egypt and Mesoamerica. There is no scientific or archaeological evidence to support any cultural link between these two pyramid-building civilizations. Instead, a pyramid is a simple solution to a structural problem – a tall structure is much more stable if it has a wide base and progressively uses less material the higher you build.
In stone tool technology there are also plenty of examples of convergent evolution across space and time, not only because of the physical constraints of flaking stone related to angles and fracture mechanics, but also because certain tool shapes are better suited to certain tasks – something we see in particular when it comes to pointed tools.
In the case of Nubian technology, under a convergent evolution scenario we might expect that it was driven by its advantages as a method for producing a specific pointed tool shape, developing out of the widespread Levallois system of flaking. Nubian technology would then be the only cultural trait that is shared by these groups, so we would see variation in the material culture that occurs alongside it.
While it is difficult to separate out scenarios of dispersal, diffusion or convergence in areas like Egypt and Arabia that are geographically very close, our discovery of Nubian technology 6000 km away in an arid part of South Africa gives us the perfect opportunity to ask how and why this technology might have arisen. This is central to the TANKwA project.
Nubian technology in South Africa
In July 2014, my colleague Matthew Shaw and I were carrying out surveys in the Tankwa Karoo as part of my PhD research. When we climbed the low rocky hill on the Tankwa River floodplain, on a farm named Tweefontein, we were expecting to find some MSA artefacts. What we actually found was a site quite unlike anything we had seen in our surveys in South Africa. It was unusual for a number of reasons.
Firstly, the sheer number of stone points; during the 12 days we spent working on the site, we recorded over 150 points – interesting since we have never found more than ten or so of this type of point at an open-air site before. Secondly, alongside the points were 120 cores (used to make points), showing Nubian Levallois technology – at the time, there had been no Nubian Levallois reported in southern Africa, it being a typically North African and Arabian type of technology. Lastly, a lot of the artefacts were made using a certain type of rock, silcrete – surprising as it geologically only occurred over 10 km away from the site. Silcrete is a fine-grained rock associated with a number of complex technological advances in the South African MSA.
Since we reported these findings, Nubian technology has been found at two other nearby sites: another open-air site, Uitspankraal 7, and a rock-shelter, Mertenhof. These sites are only about 40 km from Tweefontein, all within the catchment of the Doring River. We have also found Nubian cores in smaller numbers at 11 other locations in our surveys and retrospectively identified Nubian cores from illustrations published by Garth Sampson from his surveys 600 km to the east. Other than Sampson’s work, relatively little archaeological research has studied the arid interior region of South Africa known as the Karoo. Rather, recent MSA research has looked to the caves along the resource-rich coastline, yielding evidence of modern human behaviour. Our work on the western fringes of this distinct arid ecozone is refocusing research on the inland Karoo and revealing new MSA behavioural adaptations like Nubian technology.
The next section introduces the Tankwa Karoo before exploring our research at Tweefontein in more detail.