The final and 73rd Conference Poster Abstract Carrie Wright Calcium Isotope Analysis of Dental Enamel: a New Approach for Detecting Mammal Milk Consumption in the Archaeological Record Calcium isotope ratios (44Ca/42Ca) show promise as a proxy for milk consumption, but mass fractionation effects are small, and previous studies have been based on bone. Calcium isotopes are highly changeable in bone due to homeostatic processes, complicating the identification of milk in the diet, and requiring a different approach to assess the effects of milk consumption – using δ44/42Ca in dental enamel. Dental enamel from sheep was chosen due to the availability of modern control samples, and their relevance for understanding weaning practice. The results demonstrate that δ44/42Ca values in sheep enamel sequences reflect the two main dietary calcium contributors: milk and plants. Specifically, the modern sheep data show a 0.41 to 0.49‰ depletion in 44Ca in milk relative to grass, demonstrating that milk is a source of low δ44/42Ca. First and second molar bulk enamel samples from mature sheep show a significant mean difference, with first molars being consistently depleted in 44Ca by 0.18‰. These results reflect milk as the primary food during the first molar’s post-utero development, with weaning having occurred during the development of the second molar. The incremental results from molars of modern sheep, with known weaning history, provide an independent indication of the timing of weaning for sheep from archaeological sites, with early weaning of lambs indicating sheep were likely managed for dairying. The results also suggest a potential for use of 44/42Ca in human enamel as a proxy for milk consumption in nursing and weaning studies
Posted on: Sat, 23 Nov 2013 20:14:10 +0000
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