The long read: Out of Arabia, the story of early humanity
Nick Leech
Dr Yamandú Hilbert examining stone tools from a Palaeolithic site on the Nejd Plateau, Dhofar. Courtesy Jeffrey Rose
In March, archaeologists made a discovery in Sharjah that not only promises to shed new light on the role of Arabia in prehistory but also has the potential to rewrite the history of humankind.
The discovery was a prehistoric tool factory composed of more than a thousand stone fragments including four hand axes, scrapers that would have been used for the cleaning and preparation of animal skins and lithic preforms, rough, incomplete and unused stones still awaiting the final trimming and refinement that would have transformed them into tools.
“They may be 200,000 or even 500,000 years old, we don’t know yet, but they certainly push back the earliest evidence for human occupation in south-east Arabia,” says Knut Bretzke from Eberhard Karls University in Tübingen, Germany, the leader of the team responsible for the find made in Suhailah, north of the oasis town of Dhaid.
Like an increasing number of archaeological finds discovered across Arabia in the last decade, Bretzke’s “lithic assemblage” poses a challenge to the standard ‘out of Africa’ model of early human dispersal that has dominated the scientific consensus since the late 1990s.
“The model usually says that modern humans came out of Africa between 50,000 and 60,000 years ago, but it is important to realise that we now have archaeological evidence to support the theory that there was an earlier expansion of modern humans,” the archaeologist explains.
“And now there is more and more evidence from both genetic studies and from other finds in Arabia and Asia that there might have been multiple expansions earlier than that.”
If Bretzke’s analysis is correct, then the tools not only testify to the human occupation of Arabia at least 75,000 years earlier than was previously accepted, but Suhailah is also one of the most important prehistoric archaeological sites, not just in the UAE but across the whole of the Arabian Peninsula.
“It is undisturbed and we can now collect and study the lithics systematically and that will provide an insight into human occupation during the middle Pleistocene,” the 40-year-old archaeologist explains.
But while Bretzke remains optimistic that field work will enable his team to discover more evidence at Suhailah, he admits that arriving at a more precise date for the assemblage is unlikely.
The finds were discovered at ground level and not as a result of excavation, making dating difficult. “So far it is not possible to provide an absolute date for finds that are discovered on the surface. Of course, the axes have special characteristics that allow me to put them in a time frame between 200,000 and 500,000 years ago, but that is only based on their shape and the technology they employ.”
If dating Suhailah is to remain a matter of interpretation, the archaeologist is more confident about establishing absolute dates for his discoveries at Jebel Faya, another Sharjah site where Bretzke has overseen excavations since 2012.
“We’ve excavated about 150 square metres and we went down, at the deepest point, to about four metres fifty below the surface,” the German says.
“We’ve discovered a sequence of seven layers and we’ve collected samples and submitted them for dating. We’re still waiting for the results, but the point is that we now have a sequence of seven potentially Palaeolithic layers that can be dated and connected to those that have already been excavated with some younger Neolithic and Bronze Age finds on top.”
Bretzke hopes to have dates for these layers by the end of the year thanks to a chronometric dating technique called optically stimulated luminescence (OSL) technology.
Rather than dating the finds themselves, OSL provides a date for the layers of sediment in which they are found by measuring the amount of energy trapped inside grains of sand.
The precise amount of energy provides a date for each layer by determining the last time it was exposed to light.
“The deepest layer should date to about 125,000 years ago, but we still do not know for sure about the uppermost layers. But, given the morphology of the cave and the sedimentation, we believe that they are late Pleistocene, maybe 12,000 or 13,000 years old. We cannot be sure, but the assemblages do not look like they are Neolithic.”
For Bretzke, the importance of these layers comes from their potential to shed light not just on the early occupation of Arabia but how the Peninsula’s settlement was related to changes in climate, the origins and destinations of Jebel Faya’s inhabitants and how long they stayed.
Working with Professor Adrian Parker, a geographer from Oxford Brookes University in England, Bretzke has analysed Jebel Faya’s layers of sediment and the presence of phytoliths, microscopic silica structures that collect in plant tissue and persist in the ground long after a plant’s decay, to establish links between the site’s occupation and changes in the prehistoric climate and vegetation.
“We studied the grain size [of the sediments] and drew some conclusions about how they were deposited because you can distinguish between deposition under wet conditions and dry conditions,” Bretzke explains.
“We also found evidence for palms on the site. Of course, we don’t know whether they were naturally occurring or whether people brought them there, but they must have been somewhere in the vicinity.”
Bretzke and Parker concluded that the layers of archaeology and settlement periods at the site always related to wet periods and that layers without archaeological evidence related to dry periods.
“There is no permanent water source at Jebel Faya so you rely on precipitation and surface water. As soon as it stops raining, you would have to leave,” the archaeologist says.
“The sequence [of finds] also gives us detailed information about the technology that was used. I have assemblages with characteristics that I cannot find anywhere else and each is radically different,” Bretzke explains.
“That suggests there were pulses of settlement rather than continuous occupation but that the incoming populations came from different directions.”
Sitting midway between the Hajar Mountains and the shoreline of the Arabian Gulf, Jebel Faya is a 20-kilometre-long limestone escarpment that runs north-south through central Sharjah.
Part of its attraction to early human populations, Bretzke suggests, is that it sits on an ecotone, a point of transition between habitats where the very different environments of the mountains, the desert and the Dhaid-Madan plain meet.
“It’s a very interesting setting for hunter-gatherers because it provides you with access to three different habitats where you could hunt different species,” the archaeologist explains.
About 125,000 years ago, it is likely that the area around Jebel Faya would have been a savanna-like home to gazelles and dromedaries in desert areas, ibex or wild goats in the nearby mountains and wild asses in the plain.
Before March 2006, however, when the first pieces of a hand axe started to be identified, Jebel Faya was primarily known to research teams as a place relaxation.
“When Hans-Peter Uerpmann discovered the site there was no palaeolithic archaeology on the surface at all, but he was convinced that the situation was so perfect that he had to excavate,” Bretzke says.
“His team used to go to Jebel Faya on their days off and they would sit in the rock shelter there which made a lot of sense because the site is set back and you are protected. Even during strong winds or sandstorms on the plain excavation is always possible.”
Three metres deep and 15 metres wide, the overhanging rock shelter is Jebel Faya’s principal archaeological site, FAY-NE1.
“There may be some places in Yemen where you could find something like this but [at the moment] Jebel Faya is unique in the whole of the Arabian Peninsula,” Bretzke says.
“Usually in Arabia you have the problem that you find things on the surface, or maybe you find just one layer if you dig down, but Faya provides a series of assemblages dating to 125,000 years ago and younger, there are even two layers below 125, so there is this really long sequence that covers the complete late Pleistocene period.”