Histomorphological alteration in buried human bone from the lower Illinois Valley: Implications for palaeodietary research

Microradiographs of femur midshaft thin sections were examined in a mortuary sample (n = 119) from the lower Illinois Valley to evaluate variation in histological preservation. Twenty-three per cent of the sections displayed varying degrees of microfocal destruction due to fungal/and or bacterial invasion. Histological preservation did not vary with whole bone preservation. The activity of micro-organisms resulted in both extensive resorption of tissue and redeposition of mineral on bone surfaces. Based on the observed patterns of invasive activity, it is suggested that initial invasion and spread of organisms depend on several intrinsic properties of the tissue, including the degree of mineralization and the availability of vascular spaces to provide surfaces for tunneling. The findings indicate that histological evaluation of diagenesis should be a necessary prerequisite to dietary reconstructions which utilize invasive and non-invasive methods of analysis.