Scientists have found constructions in a cave in the south west of France that are 176,500 years old. This makes them among the oldest known human constructions. Neanderthals built structures with broken stalagmites and used them as fireplaces. This discovery proves that early Neanderthals felt confortable underground, they were well organized, mastered the use of fire and even made constructions. The French-Belgian study appeared in this week’s edition of Nature.
In 1990 a group of speleologists discovered the Bruniquel cave (in Tarn-et-Garonne) in the valley of Aveyron. In the largest chamber, located 330 metres from the entrance, they found remarkable structures assembled from whole and broken stalagmites. Two annular structures are considerable- the larger of the two is about 30 m². Four smaller accumulations were also found, and all structures contain traces of fire and burnt bone fragments.
In 1995, the first study of the site used the carbon-14 method to date a bone, the results of which gave it a minimum age of 47,600 years old (the limit of the technique). In 2013, geologist Sophie Verheyden from the Royal Belgian Institute of Natural Sciences (RBINS), Jacques Jaubert from the University of Bordeaux, Dominique Genty from the CNRS, speleologist Michel Soulier from the Société spéléo-archéologique de Caussade and co-authors investigated the structures in detail. They described all of the stalagmite fragments in detail, created a 3D model, mapped the different locations of the structures and, most importantly, took samples for new dating analyses.
Neanderthals Were First ‘Cavers’
The uranium-thorium dating technique can tell us the age of the constructions by dating the stalagmite fragments themselves. The constructions were built between the time of final growth of the stalagmites (which were used to create the structure) and the base of the stalagmite regrowths (which sealed the structure). This technique gives the precise age of 176,500 (± 2100) years old, largely predating the arrival of modern human species in Europe. The architects of these structures were therefore early Neanderthals. “These are the oldest man-made underground constructions” says Verheyden. “Bruniquel proves that Neanderthals mastered the underground environment 140,000 years before the modern humans in Chauvet and Lascaux, famous for their great cave art.”
The researchers call the broken and aligned stalagmites speleofacts. The ring-shaped constructions are made up of 400 speleofacts, which have a total length of 112 metres and weigh 2.2 tonnes. The annular structures are composed of up to four layers of aligned stalagmites. Some stalagmites were placed vertically to prop up the structure. “Building these constructions required social organisation and collaboration from this group of early Neanderthals”, says archaeologist and prehistorian Jacques Jaubert, “Neanderthals were more modern than we initially thought.”
Masters of Fire
All six constructions show traces of fire: burnt organic material and reddened and blackened calcite, the mineral in stalagmites, were found. Dating of these fragments shows that they are as old as the constructions themselves. Magnetic measurements reveal that the coloured zones were heated and spectroscopic analysis of the organic material confirms its calcination. Jaubert: “The study proves this group of Neanderthals were familiar with the use of fire: it would have been impossible to occupy the pitch black cave at a depth that is no longer exposed to daylight”. A 2011 study concluded that Neanderthals were the first human species to master the use of fire 300,000 years ago when they began to cook.
Scientists do not believe that Neanderthals or modern human species occupied the cave for an extended length of time- they lived at the entrance. So, what was the function of these structures far from the cave entrance? Did they have a ritual or symbolic meaning? Did they serve as water reserves or simply as a refuge? The researchers hope to address these questions in the future.
For thousands of years the Neanderthal constructions were perfectly preserved inside the cave and protected from weathering. After the Neanderthal period, the entrance of the cave collapsed and since then no humans had entered Bruniquel until 1990 when cavers rediscovered the entrance.
This study was carried out by a team of researchers from Belgium, France, Switzerland, China and the United States of America and has been published in Nature.
This study was (partly) funded by BELSPO and the Ministery of culture, the Direction régionale des affaires culturelles de Languedoc-Roussillon - Midi-Pyrénées, Toulouse.