Uncovering the chemical secrets of burned bones

Abstract

By examining burned bones, anthropologists can gather clues about how an ancient culture dealt with its dead or cooked its meat. In a new study, researchers report that Fourier transform infrared (FTIR) spectroscopy can not only differentiate bone burned in a fire from unburned bone, but can also distinguish between burned bone and fossilized bone (Anal. Chem. 2018, DOI: 10.1021/acs.analchem.8b02868). David Goncalves of Portugal’s Directorate General for Cultural Heritage and colleagues applied their FTIR-based method on modern human bone samples burned experimentally at various temperatures, cremated human remains from Bronze and Iron Age burial sites, and fossilized bones of ancient reptiles. They found that a characteristic hydroxyl peak reliably identified bone burned at temperatures above 700 oC—indicative of direct exposure to fire—in both modern and ancient bone samples. Fossilized bone, by comparison, rarely showed the hydroxyl signal. Knowing the burn temperature of a bone sample provides informa...