EFFECT OF DIET, PHYSIOLOGY AND CLIMATE ON CARBON AND NITROGEN STABLE ISOTOPES OF COLLAGEN IN A LATE PLEISTOCENE ANTHROPIC PALAEOECOSYSTEM -MARILLAC, CHARENTE, FRANCE

In fossil mammal bones and teeth from Marillac (40,000-45,000 years BP ), collagen has been found to be preserved. This collagen presents a s imilar amino acid composition to modern collagen. An isotopic differen ce between collagen of herbivorous and carnivorous species is clearly documented in this paper and it is shown that the decrease of the amou nt of collagen in bones and teeth through diagenesis has not altered t he original isotopic signal. It has been possible to demonstrate the c arnivorous diet of Neanderthals. In addition, more subtle isotopic dif ferences have been documented between the different species within eac h trophic group consumed. These differences can be linked to physiolog y, or to particular kinds of food of each animal species. Another isot opic signal due to nursing effects has also been observed. A young mam mal suckling its mother's milk is one trophic level higher than an adu lt of the same species. Consequently, the collagen of deciduous teeth records an isotopic signal from the food consumed before weaning. Also , in species where most of the tooth growth occurs before weaning time , the collagen of permanent teeth records, in part, information about the milk diet. Thus the N-15 composition of such teeth is different fr om the isotopic composition of bones in the same individual. The varia tion of the N-15 composition of bone collagen along the stratigraphica l sequence of the site shows that this isotopic signal may also be use d for the palaeoclimatic reconstruction; for example, evidence of an a rid period is seen in the layer #7 in Marillac.