Radiocarbon Ecology of the Land Snail Helix Melanostoma in Northeastern Libya

Terrestrial gastropods are problematical for radiocarbon (14C) measurement because they tend to incorporatecarbon from ancient sources as a result of their dietary behavior. The 14C ecology of the pulmonate land snail, Helixmelanostoma in Cyrenaica, northeastern Libya, was investigated as part of a wider study on the potential of using terrestrialmollusk shell for 14C dating of archaeological deposits. H. melanostoma was selected out of the species available in the regionas it has the most predictable 14C ecology and also had a ubiquitous presence within the local archaeology. The ecologicalobservations indicate that H. melanostoma has a very homogenous 14C ecology with consistent variations in F14C acrosssample sites controlled by availability of dietary vegetation. The majority of dated specimens from non-urbanized samplelocations have only a small old-carbon effect, weighted mean of 476±48 14C yr, with between ~1% and 9% of dietary F14Cfrom non-organic carbonate sources. Observed instabilities in the 14C ecology can all be attributed to the results ofintense human activity not present before the Roman Period. Therefore, H. melanostoma and species with similar ecologicalbehavior are suitable for 14C dating of archaeological and geological deposits with the use of a suitable offset.