A Morphological Investigation of Burnt Animal Bone and an Evaluation of its Utility in Archaeology

Abstract

In 1984 Shipman and colleagues proposed a series of stages by which temperature of burning could be recognized from bone colour, mineral crystal size and surface morphology using the scanning electron microscope (SEM). This study investigates whether the changes in colour and surface morphology recognized for large mammal bone can be observed on other vertebrate bone, and if so whether at the same temperatures. Diagenesis is also considered in terms of its effects on crystal structure, and the relevance of the temperature-induced diagnostic changes assessed for archaeological bone. The results indicate that mammal and non-mammal bones undergo a similar range of colour and morphological changes with heating, but the temperature at which each stage is reached may vary. A wider range of surface morphologies was observed on bone exposed to temperatures above 700°C than has been documented before. Similar surface modifications have been recognized on some archaeological bones, but diagenetically-induced surface erosion and recrystallization may complicate interpretation. Inspection using a low power optical microscope is a valuable precursor to SEM investigation, and may sometimes provide sufficient proof of heating.