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Published online by Cambridge University Press:  13 May 2021

Rachel Wood*
Research School of Earth Sciences, Australian National University, Acton, 2601, Australia School of Archaeology and Anthropology, Australian National University, Acton, 2601, Australia
Andre Barros Curado Fleury
School of Archaeology and Anthropology, Australian National University, Acton, 2601, Australia
Stewart Fallon
Research School of Earth Sciences, Australian National University, Acton, 2601, Australia
Thi Mai Huong Nguyen
Anthropological and Palaeoenvironmental Department, The Institute of Archaeology of Vietnam, Hanoi, Vietnam
Anh Tuan Nguyen
Anthropological and Palaeoenvironmental Department, The Institute of Archaeology of Vietnam, Hanoi, Vietnam
*Corresponding author. Email:


In hot environments, collagen, which is normally targeted when radiocarbon (14C) dating bone, rapidly degrades. With little other skeletal material suitable for 14C dating, it can be impossible to obtain dates directly on skeletal materials. A small amount of carbonate occurs in hydroxyapatite, the mineral phase of bone and tooth enamel, and has been used as an alternative to collagen. Unfortunately, the mineral phase is often heavily contaminated with exogenous carbonate causing 14C dates to underestimate the true age of a sample. Although tooth enamel, with its larger, more stable crystals and lower porosity, is likely to be more robust to diagenesis than bone, little work has been undertaken to investigate how exogenous carbonate can be effectively removed prior to 14C dating. Typically, acid is used to dissolve calcite and etch the surface of the enamel, but it is unclear which acid is most effective. This study repeats and extends earlier work using a wider range of samples and acids and chelating agents (hydrochloric, lactic, acetic and propionic acids, and EDTA). We find that weaker acids remove carbonate contaminants more effectively than stronger acids, and acetic acid is the most effective. However, accurate dates cannot always be obtained.

Research Article
© The Author(s), 2021. Published by Cambridge University Press for the Arizona Board of Regents on behalf of the University of Arizona

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