MEASUREMENTS AND RELATIONSHIPS OF DIAGENETIC ALTERATION OF BONE FROM 3 ARCHAEOLOGICAL SITES

Four diagenetic parameters have been chosen to represent the state of diagenesis of bone buried on archaeological sites. They are: histological preservation, protein content, crystallinity, and porosity. How these parameters are measured is described and results from populations of bones from three different sites are presented. The results show the extent and variation in the degree of change, both within a site and between sites. In particular the correlations between diagenetic parameters are examined, which give clues about the processes which cause alteration. The value of porosity determinations (both at the intercrystalline level, and at coarser levels) in revealing the degree of diagenetic change in bone, and in underlying the dynamics of the interaction between buried bone and the surrounding water is stressed. The data also indicate (but are too restricted to prove) the following: Microbiological attack is generally complete within less than 500 years; Substantial levels of protein may remain in bone after maximal micromorphological alteration; Loss of protein appears to be independent of other diagenetic change; The correlated loss of microporosity with increase of crystallinity suggests these changes may arise from the dissolution, perhaps with subsequent recrystallization, of the smallest hydroxyapatite crystallites.