An exceptionally high density of ‘giant’ handaxes has been uncovered at an archaeological site in Spain, the first such discovery outside Africa.
An international team of researchers, including Griffith University’s Dr Mathieu Duval and the University of Adelaide’s Dr Martina Demuro and Dr Lee Arnold, has performed a comprehensive study on the site, named Porto Maior, in the Miño River basin in north-west Spain.
Their findings have now been published in open-access journal Scientific Reports.
The study, led by E. Méndez-Quintas of Spain’s National Research Centre for Human Evolution (CENIEH), may suggest the coexistence of at least two different human groups in the Iberian Peninsula about 200,000 to 300,000 years ago.
The excavation of fluvial sediments at the site comprised a total of about 3700 lithic artefacts, 290 of which were used in the assemblage – primarily composed of – of Large Cutting Tools (LCTs) studied by the researchers.
Dating the axes (pictured right), which measure about 18 centimetres long, was performed by the Australian team members, with Dr Duval conducting Electron Spin Resonance (ESR) testing, and Drs Demuro and Arnold conducting luminescence dating.
“We applied the two dating techniques in an entirely independent way,” Dr Duval – a member of Griffith’s Australian Research Centre for Human Evolution (ARCHE) – said.
“We were quite pleased to realise that we obtained highly consistent results. This gave us good confidence in our dating work and enabled us to produce a robust chronology for Porto Maior.”
The researchers’ results indicate that the lithic tool-bearing deposits date to between 293,000 and 205,000 years ago, raising questions regarding the origin and mobility of prehistoric populations in Europe during the Middle Pleistocene (between 773,000 and 125,000 years ago).
According to laboratory analyses, the handaxes – which are characteristic of so-called Acheulean technology due to their distinctive shape – were not configured on-site, but brought from elsewhere.
The high density of tools found at Porto Maior parallels trends at Acheulean sites in Africa and the Near East, reinforcing the possibility of an African origin for the Acheulean tradition of south-west Europe.
While the age of the Porto Maior site is consistent with previous findings on the Iberian Peninsula with respect to the expansion of the Acheulean tradition, there is also evidence of completely different tool assemblages being used across Spain during the same era.
The researchers say that the technological overlap suggest the co-existence of culturally distinct human populations of different geographical origins.
“The African affinities of the LCT assemblage at Porto Maior may be consistent with a technology brought in by an ‘intrusive’ population, which differed from the core and flake industries of established human groups in south-west Europe,” Dr Arnold said.
Added Dr Demuro: “These chronological findings have important implications for understanding the complex human occupation history of the continent.”
Aspects of the ESR and Luminescence dating studies were covered by Australian Research Council (ARC) Future Fellowship Grants FT150100215 (Mathieu Duval) and FT130100195 (Lee J. Arnold) and Early Career Researcher Award DE160100743 (Martina Demuro).