Modification chimique des os fossiles et de différents stades de préservation osseuse en relation avec les conditions du sol

The preservation of human and animal bone from four prehistoric sites of different age was investigated in relation to soil conditions. The surface, density, hardness, and organic content of the bones are correlated and can thus serve to describe the state of preservation of the bone. Correlations between osseous deterioration, soil acidity (as measured by pH) and the calcium content of the soil were found to be significant. Elements associated with soil contamination (iron, aluminum, manganese) are found in significantly higher proportions in poorly preserved bones. Analysis of trace elements from the bone mineral used for diet reconstruction in the same bone samples showed that various amounts of magnesium are lost through leaching. Therefore, magnesium is excluded from use for diet reconstruction. The zinc concentrations are not altered. The elements barium and strontium appear not to be so sensitive to diagenesis. Zinc, barium, and strontium may serve as useful prehistoric dietary indicators.