Curve-fitting Micro-atr-ftir Studies of the Amide I and Ii Bands of Type I Collagen in Archaeological Bone Materials

Bone and alike materials, including ivory and antler, have an important place among prehistoric remains as they record a wealth of information on the past ways of life in the form of morphological and structural changes as well as in their chemical and isotopic composition. Such materials generally exhibit a high degree of hierarchy and essentially consist of collagen molecules and hydroxyapatite crystals at the nanoscale. The structure and the chemical composition of archaeological bone material may be modified by interactions with the burial environment. The present work focuses on the characterisation of structural modifications of the type I collagen, especially its secondary structure, preserved in archaeological bone remains induced by diagenesis. Therefore, the potential of ATR-FTIR combined with curve-fitting of the amide I and II bands is evaluated. Using this method, the conservation state of the collagen secondary structure has been determined for well preserved archaeological bone material from Neolithic layers of two stations (19 and 21) at the lake site of Chalain (Jura, France).