The age of hominin footprints discovered in southern Spain in 2020 has just been reassessed. The study shows that they date back to around 300,000 years old and belong to pre-Neanderthals.
In June 2020, footprints attributed to hominids were discovered in southern Spain, bordering El Asperillo beach, producing a small revolution in the scientific world. Dating of geological units directly covering the paleosol in which these footprints are imprinted revealed that they were approximately 106,000 years old. This chronological context then made it possible to attribute the footprints to Neanderthal man, opening an interesting discussion on the evolution of this community and its ecological role in this region at a time when the climate was particularly favourable.
However, new elements have come to disrupt this pattern. Based on another dating method, a team of scientists has just revealed that the footprints may actually be much older. And that changes everything!
Footprints almost 300,000 years old!
Where the previous study had focused on dating the sediments covering the tracks, thus producing an upper bound for the age of the footprints, this time the researchers focused on dating the paleosol itself. To do this, they used a luminescence dating technique. This technique makes it possible to determine the absolute age of sediments that have been exposed to sunlight. In fact, some minerals, once buried, are capable of storing an unstable charge of electrons within their crystal lattice linked to their previous exposure to ionizing radiation from the sun. By stimulating these minerals (quartz and feldspar) with light and analyzing their luminescent signal, it is possible to estimate how long the paleosol layer has been buried.
The results obtained in the context of this new dating of the El Asperillo samples are nothing short of surprising. Published in the magazine Scientific reports, reveal that the footprints are 295,800 years old, nearly 190,000 years older than previously assumed. This new result therefore makes this site a unique place in Europe, since there are very few hominin footprints dating from this period. The site of El Asperillo is also particularly important: today it contains more than 300 footprints, 10% of which are in an excellent state of conservation.
A walk on the beach among pre-Neanderthals
But are they Neanderthals? With this new appointment, doubt makes its way. For scientists, analysis of foot morphology suggests that hominids who walked on this beach in the Middle Pleistocene were more likely ancestors of the Neanderthal line. The climatic environment associated with this presence is also very different from what was previously assumed. The Middle Pleistocene period is in fact a turning point from a climatic point of view. It marks the transition between a warm period (360,000 to 300,000 years ago) and a glaciation episode (300,000 to 240,000 years ago). El Asperillo’s footprints are the only ones known to date from this major climate transition in Europe.
This new chronology therefore implies a modification of the scenario in force until then on the presence of human communities in the Gulf of Cadiz, then subject to a more temperate and more humid climate compared to the rest of Europe where the drop in temperature was already taking place. . The vegetation was then very dense in this region and the sea level about 60 meters below the current one. The hominids would thus have walked in the muddy sediments of a vast alluvial area bordering the coast.
This reassessment of the age of these footprints therefore provides valuable insight into the evolution of human occupation in Europe during the Pleistocene.