Nitrogen isotope dating

Other surveys and summaries of stable isotope analysis in archaeology may be found in Schwarcz & Schoeninger (1991); van der Merwe (1992); Ambrose (1993); Schoeninger 1995; Katzenberg & Harrison (1997); Larsen (1997); Tykot (2004), and Tykot (2006). My experience in bone chemistry dates to 1990 when I became the manager of the Archaeometry Laboratories in the Anthropology Department at Harvard University. van der Merwe, the new director of the laboratory, was the first archaeologist to use stable isotopes, and the methods I learned were adapted from those in use in his laboratory in Cape Town, where he has recently returned as Professor of Natural History. Effect of diet quality and composition on the isotopic composition of respiratory CO2, bone collagen, bioapatite, and soft tissues. Small differences in the ratios of these isotopes (12C/13C, 15N /14N) can be measured by isotope ratio mass spectrometry using samples smaller than 1 milligram. High precision isotope measurements are reported using the delta notation (d13C, d15N) relative to internationally recognized standards and are expressed in parts per thousand or per mil (‰). Experimental data have indicated that different bone tissues reflect different components of the diet (Ambrose and Norr 1993; Tieszen and Fagre 1993). "Stable isotope analysis of bone collagen and apatite in the reconstruction of human diet: a case study from Cuello, Belize," in Archaeological Chemistry. In general, bone collagen is disproportionately produced from the protein portion of the diet, while bone carbonate and tooth enamel carbonate (both a calcium hydroxyphosphate, called apatite) are produced from a mixture of dietary protein, carbohydrates and fats.

Samples are analyzed on a second Finnigan MAT mass spectrometer equipped with a Kiel III individual acid bath carbonate system. The effects of sample treatment and diagenesis on the isotopic integrity of carbonate in biogenic hyroxylapatite. Stable Isotopes as Indicators of Change in the Food Procurement and Food Preference of Viking Age and Early Christian Populations on Gotland (Sweden). Carbon and nitrogen isotope ratios in human bone may be used to reconstruct prehistoric diet because of differential fractionation, between certain plant groups, of atmospheric carbon dioxide during photosynthesis and of nitrogen during fixation or absorption. ACS Symposium Series 625, Washington, DC: American Chemical der Merwe, N. There are two stable isotopes each of carbon (12C, 13C) and nitrogen (14N, 15N), with 12C and 14N by far the most common in nature. The analysis of bone apatite,which is derived from all food groups, should allow the identification of just a few percent maize or other C4 resources in an otherwise C3-based diet. The nitrogen isotope ratios for plants depend primarily on how they obtain their nitrogen - by symbiotic bacterial fixation or directly from soil nitrates - and these values are similarly passed along through the food chain accompanied by an approximately 2-3‰ positive shift for each trophic level, including between mother and nursing infant.

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