New research led by Prof. Ari Matmon of the Hebrew University of Jerusalem, Prof. Omry Barzilai of the University of Haifa, and Prof. Miriam Belmaker of the University of Tulsa has revised the age of the 'Ubeidiya site in the Jordan Valley. By combining three advanced dating methods, cosmogenic isotope burial dating, magnetic reversal analysis, and uranium-lead dating of fossil snail shells, the team established that the site is at least 1.9 million years old, significantly older than previous estimates of 1.2 to 1.6 million years.
'Ubeidiya has long been important for its early evidence of the Acheulean stone tool tradition, which includes large, double-sided hand axes. The site also contains a rich collection of animal fossils from African and Asian species, several now extinct. The revised dating places it at roughly the same age as Dmanisi in Georgia, another key early human site, suggesting that different groups of ancient humans carrying distinct tool technologies, such as the simpler Oldowan and the more advanced Acheulean, spread beyond Africa simultaneously.
The researchers encountered a complication: initial cosmogenic isotope measurements suggested a much older age of about three million years. They determined that the discrepancy arose because the sediments had been repeatedly deposited, buried, and recycled within the Dead Sea rift, carrying an earlier geological signature. "The exposure-burial history that emerges from the model implies recycling of sediments previously deposited and buried in the rift valley… and then redeposited along the 'Ubeidiya paleo lake shoreline," the team explained. By accounting for this process, they reconciled the evidence and confirmed the site's revised age.
The findings indicate that early human migration into new territories was already underway 1.9 million years ago, potentially involving multiple populations with different toolmaking traditions.