Dating Marine Shell: A Guide for the Wary North American Archaeologist

Abstract Radiocarbon dates on marine shell and other materials of origin appear significantly older than contemporaneous samples terrestrial/atmospheric origin. Misunderstandings regarding the mechanisms that give rise to this “marine reservoir effect” (MRE), terminology used define it, mathematics describe it cause many coastal archaeologists distrust or misinterpret dates. The recent release a reformulated 14 C calibration curve for (Marine20), which necessitates recalculation all local age corrections, may add confusion. Here, we review benefits dating shell; provide plain-language explanation mechanical, chemical, biological, cultural processes disparities associated with MRE; offer advice intending date shell. Our hope is these comments will not only aid in planning interpretive stages research but also assist assessing reliability legacy chronologies based materials. More broadly, encourage careful evaluation sources uncertainty chronologies, whether terrestrial