Lack of stone tools explains missing human traces in Arabian desert

A team of researchers trekked 1,500 kilometers across the Rub' al Khali, a massive sand desert in the Arabian Peninsula, to find evidence of ancient human settlements.

The researchers sought clues about how early humans might have moved out of Africa and into Asia during the Pleistocene epoch. They looked for signs of life around ancient lakes that appeared during wetter periods in history. The team identified evidence of ancient lakes at 55 of the 125 locations they investigated.

These deposits date back approximately 122,000 to 67,000 years ago. Despite the presence of these water sources, the team found no traces of human activity or artifacts. The researchers concluded that water alone was not enough to support sustained human habitation. They found that only 10 of the 125 sites contained knappable stone, which ancient people needed to manufacture tools. All of these stone sources were located on the outer edges of the desert.

The central basin of the desert consists of carbonate and evaporite formations that do not provide suitable materials for tool making. The study suggests that prehistoric Arabia functioned like a lithic archipelago. Humans likely only settled in specific zones where both water and stone resources overlapped. The researchers noted that 57 percent of the terrain with water access lacked the necessary stone for tool making.

They argue that migration models must include geological data to accurately predict where ancient populations could live.