Anyone who has ever collected shells and shells on the beach knows that these are often not completely intact. Sometimes small pieces have broken off, sometimes they have one or more holes. These are mostly created by natural processes. In the case of an archaeologically relevant find, the question arises as to whether perforations in such bowls were caused intentionally or simply naturally.
Marjolein D. Bosch from the Austrian Archaeological Institute ÖAW faced exactly this challenge – the determination of human action. The researcher wanted to prove that over 400 pieces of the fusiform shells of Columbella rustica sea gastropods from the Early Upper Paleolithic discovered at the Ksâr ‘Akil archaeological site in Lebanon had been deliberately perforated to make jewelry.
“This purpose was suspected for a long time, now I wanted to investigate it and prove it scientifically,” explains Bosch. For this, the native Dutchwoman collected housings of the species Columbella adansoni on the beach in Tenerife, Spain, which are very similar to those of Ksâr ‘Akil. Most importantly, they share the general distribution pattern of shell thickness necessary for the study.
“First, pristine shells were scanned for robust and fragile zones using micro-CT scans. We then made 3D models of the shells, which showed the exact structure of the different mussels, i.e. where they were thinner or thicker,” says Bosch. Based on the models, it was now possible to determine where the perforations were located. The result: “In the housings I collected from the Spanish beach, the vast majority of the perforations occurred in structurally weak zones,” explains the expert. “In contrast, in our archaeological finds, we found a higher frequency of perforations in more robust zones and a higher uniformity in their location, size and shape.”
From this it can be clearly concluded that the snail shells were deliberately chosen on the one hand and perforated in the course of a planned manufacturing process on the other hand in order to then hang them on chains or clothing. “These snails are too small to eat, so they were collected and brought to the site for other reasons. In addition, the standardization of perforation shape, size, and distribution indicates formalized manufacturing processes,” emphasizes Marjolein D. Bosch, whose The results of the investigation were also recently published in the “Journal of Archaeological Science: Reports”.
But what were these jewels used for? The researcher also dealt with this. “Since these served no purpose, such as subsistence or tool use, we assume they were ‘symbolic’,” says Bosch. So had a symbolized meaning that was understood by many people – a kind of common language. So it could probably be a matter of marking groups: jewelry is used to show where you come from and where you belong. Bosch intends to continue researching in this direction in the future, but the scientist also plans to examine the type of suspension by means of an analysis of signs of wear.