Even where water once pooled, the Empty Quarter kept early humans at bay.
Key points
- Ancient lake deposits are widespread in the Empty Quarter, but no archaeological artifacts have been found at those sites.
- The scarcity of knappable stone in the desert’s central basin likely prevented early humans from establishing lasting camps despite water availability.
- The study’s model shows that 57 % of water‑accessible terrain lacked suitable lithic material, redefining the habitability map of Pleistocene Arabia.
- Future models of human dispersal out of Africa must consider both hydrological and geological factors to avoid overestimating viable settlement zones.
The Rub' al Khali – the world’s largest continuous sand desert – stretches roughly 1,000 km across the Arabian Peninsula. During wetter phases of the Pleistocene, temporary lakes and green corridors are thought to have dotted the landscape, offering potential routes for early humans moving out of Africa.
In a new Nature paper, a multinational team trekked about 1,500 km of the desert, investigating 125 sites for lake deposits and archaeological traces. They identified ancient lake evidence at 55 locations dated to roughly 122,000–67,000 years ago, yet “we stood on the shore of one ancient lake after another, yet found nothing made by human hands,” reported geoarchaeologist Rudolf Dellmour of the University of Vienna.
Lake Discoveries Across the Desert
The researchers noted that only 10 of the surveyed spots contained geological deposits of knappable stone – the raw material needed for stone‑tool production – and all of these were on the desert’s outer margins. The central basin’s carbonate and evaporite formations, while capable of holding water, were unsuitable for crafting tools, a prerequisite for sustained habitation.
Using the field data, the team built a model that integrates water availability with lithic resource distribution. Their calculations indicate that 57 % of terrain accessible to water in prehistoric Arabia lacked suitable stone. The authors describe “Green Arabia” as a “lithic archipelago,” where islands of habitability were defined as much by geology as by climate.
Stone Tool Scarcity Limits Settlement
Prehistoric archaeologist Emanuele Cancellieri, who was not involved in the study, emphasized that the work “subjects a well‑known idea to an ambitious study.” He added that migration models ignoring raw‑material constraints may overestimate the area early stone‑tool‑dependent populations could occupy.
Reader questions
Why didn't early humans settle near the ancient lakes discovered in the Rub' al Khali?
Because the central desert’s geology provided little or no knappable stone, making it difficult to produce the stone tools essential for survival.
How many lake sites were identified during the expedition?
Evidence of ancient lakes was found at 55 of the 125 locations surveyed.
What does the research suggest about migration routes through Arabia?
It suggests that water alone was insufficient; the co‑occurrence of water and lithic raw materials created a patchwork of habitable zones, limiting where stone‑tool‑dependent groups could settle.
Source: sciencealert.com
