GEOCHEMICAL CRITERIA FOR THERMAL ALTERATION OF BONE

In bones not influenced by other diagenetic effects, heating events ca n be reflected in changes in the relative concentrations of constituen t amino acids that alter the collagen-like pattern in bone to a non-co llagen-like pattern with an increase in the relative NH3 levels. The r atio of glycine (Gly) to glutamic acid (Glu) can be used as an index o f a collagen-like or non-collagen-like pattern. For a group of eight b one samples from a southwestern United States Pueblo II period Anasazi site dated to about AD 1100, amino acid composition, as characterized by Gly/Glu values, along with NH3 data, clearly indicated which bone fragments had been subjected to one or more heating events. The use of Gly/Glu and NH3 values for the purpose of inferring heating events ma y not be accurate for bones which have experienced other significant d iagenetic effects not related to heating.