Bone density fractionation has a potential to recover lifetime signatures by separating out diagenetic signals as well as by tracing the different stages of an individual's diet. In methodological terms, this study presents improvements on Bell et al. 's work (200 I) on particle size distribution. The validation of the method was carried out by bomb radiocarbon dating by tracking the different osteonal ages of the individual's lifetime. I have shown that 14C dating of the collagen and the tissue age of the bone fractions can be qualitatively compared against models of bone turnover, using 14C pulse of the atmospheric bomb curve. The application of the method has been extended to bone apatite carbonate. Although bone carbonate is important in palaeodietary studies, it has been questioned so far due to the difficulty of removing diagenetic carbonate and the lack of any suitable test for validity. I have obtained consistent results using combined density fractionation and differential dissolution methods; that is, lower (iI3Capa values are observed in lighter, less diagenetically altered density fraction, from bone carbonate. Three archaeological sites (i.e. Danebury, Lechlade, Balatonaszarsz6) tell a similar story, and it is difficult to find any particular relationship between the preservation state and the validity testing. Although there is a slight improvement in (i13Capa values in bone carbonate, which also agrees with FTIR SF results, there is a consistent shift in 14C results for bone and enamel carbonate, which implies a high level of modem contamination compared to the collagen dates. In addition, I have shown one possibility, which is that (i13C and 14C results ofenamel-bone carbonate and collagen may be used as one test ofvalidity. The various methodological developments and archaeological applications presented in this thesis contribute to the understanding of the usage of bone carbonate and provide an extensive individual's dietary history using combined bone collagen and carbonate values. Future study on bone carbonate should consider acquiring a better understanding ofbone diagenesis and the methodological development.