Garbage, Storage or a Mussel Oven? a Case Study of a Shell Midden from Western Poland

Shell middens are common finds recorded at Polish archaeological sites dating from the Neolithic to Iron Age; however, very little is known about the acquisition and exploitation of mussels by prehistoric communities. An archaeological feature discovered recently at Kiekrz (western Poland) has provided us with a rare opportunity to conduct complex research on a representative and large sample. Our study aimed to recognise the function of the pit, the character of the shell deposit, its chronology, the season of shell collection and environmental conditions that prevailed in the settlement's time. The investigations included multi-faceted analyses of archaeological finds (pottery, animal bones, and mollusc shells) and charcoal remains, δ13C and δ18O shell composition, and C14 dating. The results of the research indicate that the molluscs of Unio were deliberately collected for food c. 1500 cal. BC. They were probably harvested during late summer from the nearby lake. Then the molluscs were steamed in a kind of earth oven. Pine and oak wood from the immediate vicinity was used as firewood during the molluscs processing. After the meal, shells were probably stored in the pit for further use.