The El Salt deposit, one of the Neanderthal archaeological sites most important in the Western Mediterranean, it has eleven well-preserved and overlapping outdoor home structures.
Until now, it was not clear whether these houses were formed during successive short-term occupations, or in fewer occupations, but longer term. The analysis of the remains associated with prehistoric bonfires gives new clues about it.
"These sediments contain very valuable information on the behavior of their manufacturers, as well as on the surrounding vegetation," says Lucia Leierer, researcher at the Antonio González Biorganic Institute of the University of La Laguna, and main author of the study published by the PLoS ONE magazine.
The authors believed that structures of El Salt they represent a set of synchronous bonfires on a single Neanderthal occupation surface. The work reveals that, in reality, it was a succession of occupation soils spaced in time, all of them with bonfires.
"We have verified that the Neanderthals who occupied this site, in the central Iberian Mediterranean area, did so on a recurring basis, but ephemeral and with long periods of abandonment," says Leierer.
The investigation reveals a high mobility of Neanderthal groups, confirmed by long periods of abandonment of the site.
To reach this conclusion, Spanish scientists examined the different layers within home structures to evaluate the occupation times within the study unit.
In addition, they conducted an analysis of lipid (fat) and isotope biomolecular residues to obtain information on possible foods and fuels.
What the sediments of Neanderthal bonfires reveal
The results show that the burned organic matter present in the homes of El Salt was rich in herbivore excrement Y flowering plant residue. "This tells us long periods of time when the Neanderthals were not there," adds the researcher.
These plant remains neither were they burned in their fresh state, the scientists point out, "so possibly the season of human occupation was not autumn," emphasizes Leierer. The analyzes also indicate that the plant remains are not pine, the main fuel for bonfires, so Neanderthals were able to bring fuel from outside.
According to the authors, data indicate at least four successive short-term Neanderthal occupations, separated by relatively long periods of time, possibly based on the seasons.
Leierer L, Jambrina-Enríquez M, Herrera-Herrera AV, Connolly R, Hernández CM, Galván B, et al. (2019) "Insights into the timing, intensity and natural setting of Neanderthal occupation from the geoarchaeological study of combustion structures: A micromorphological and biomarker investigation of El Salt, unit Xb, Alcoy, Spain”. PLoS ONE 14 (4): e0214955. https://doi.org/10.1371/journal.pone.0214955.
Via Adeline Marcos in Sinc.