Quaternary Science Reviews 23 (2004) 959–965 Bone as a stable isotope archive for local climatic information Robert E.M. Hedges a, *, Rhiannon E. Stevens a , Michael. P. Richards b a Research Laboratory for Archaeology and the History of Art, University of Oxford, 6 Keble Road, Oxford OX1 3Qj, UK b Department of Archaeological Sciences, University of Bradford, Bradford, West Yorkshire BD7 1DP, UK Received 19 February 2003; accepted 13 June 2003 Abstract This brief review outlines the contribution that the study of stable isotope composition in bone can make to palaeoclimatic investigation, with the focus almost entirely restricted to the last 50,000 years in NW Europe. Bone can provide a useful archive of the prevailing isotopic condition, and represents a quite different, and often less specialised, sampling of the environment than most other archives. On the other hand, chronological sequences—and dating generally—can be a problem, and the link between the isotopic value registered in the bone, and the environmental conditions which gave rise to it, is both complex and not fully understood. Carbon, oxygen and nitrogen isotopes are all available from bone (nitrogen only where sufficient protein (collagen) survives), and are all subject, in different ways, to climatic influences such as temperature, rainfall, changes in floristic composition, and soil chemistry. These are all briefly discussed, and the datasets that are being published are considered in the context of the environmental information they provide. Undoubtedly environmental signals are recoverable, but their interpretation is still primitive. A dataset for carbon and nitrogen isotope composition of herbivores that spans the last 50,000 years is shown together with some of the issues it raises. r 2004 Elsevier Ltd. All rights reserved. 1. Introduction Isotopic fractionation can often be observed during the cycling of light elements at the earth’s surface (Hoefs, 1997). Any particular transformation is likely to involve differences in kinetics between isotopes, or differences in equilibrium compositions; whether these are manifested in isotopic composition change depends on the extent to which any given process goes to total conversion. The effect of the environment on these processes can be ubiquitous; e.g. kinetics and equilibria alter with temperature, yields change with overall productivity, etc., and there are now many well established proxy records whose isotopic values (usually d 18 O or d 13 C) record some particular effect of climatic state. For isotopic information, stratigraphic deposits pro- vide especially valuable records, such as foraminifera in deep-sea cores, water and atmosphere in ice cores, carbonate deposits in lakes and speleothems, and organic deposits in lake sediments and loess deposits. Most climatic work has focussed on O isotope effects, driven largely by the hydrological cycle, but increasingly information is being sought from archives involving organic materials (Stuiver and Braziunas, 1987; Hatte et al., 2001; Talbot, 2001). This is partly in response to the need to relate terrestrial records to the clearer signals of the marine and arctic sequences, and partly to develop the realisation that isotopic signatures can enhance the existing evidence provided by organic remains. It is within this general context that we discuss the relatively small amount of information so far available from studying bone stable isotopic values. 2. Why study the stable isotopes of bone? Bone, although a complex material, is well defined through metabolic processes, and its composition is directly determined by what the animal eats or drinks. The chemical composition of bone alters during burial, but such diagenetic processes are clearer and better studied than is the case for other organic material, so that the fidelity of the isotopic record is generally reliable. Bone combines several isotopes in one entity, and is especially useful as a record for nitrogen (see ARTICLE IN PRESS *Corresponding author. E-mail address: robert.hedges@rlaha.ox.ac.uk (R.E.M. Hedges). 0277-3791/$ - see front matter r 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.quascirev.2003.06.022