A02_03

Examining carbon sources and radiocarbon dates on food plants and animals to understand offset dates on charred food crust

Scott Cummings L¹, Varney R¹

¹PaleoResearch Institute, Inc., Golden, United States

When ceramics, charred food crust, or even bone collagen yields ages older than expected, the Freshwater Reservoir Effect is suspected in several parts of Europe and North America, as well as elsewhere in the world. Research has examined whether or not regional offsets may be calculated or estimated and also whether or not some or all of the ancient carbon may be removed, particularly from ceramics or charred food crust. Although we expect that all carbon entering an organism is available for deposition into the cells of that organism, few studies have examined distribution of radiocarbon dates within single organisms by tissue type. In light of the fact that individual vessels may be used to cook or process multiple meals and foods, we have focused a portion of our research on radiocarbon dating several portions of that food prior to the time when it become food for human consumption. After radiocarbon dating bone collagen from four fish caught in 1939 and observing offsets varying from approximately 300 to 1200 radiocarbon years, we have broadened our research to include radiocarbon dating multiple samples (tissue and bone collagen) from reference animals, as well as stomach contents. For plants we examine seeds, stems, and leaves. Stomach contents of aquatic animals have yielded greater offsets than did either the flesh or bone collagen of those animals. We compare this information with radiocarbon dates on charred food crusts from various projects in the US.