ECOLOGICAL AND PHYSIOLOGICAL VARIABILITY OF SR/CA AND BA/CA IN MAMMALS OF WEST EUROPEAN MID-WüRMIAN FOOD WEBS

Abstract

The Middle to Upper Paleolithic transition in Western Europe is characterized, from an ecological point of view, by large-ungulate communities adapted to cold climatic conditions. The aim of this study is to reconstruct the trophic relationships prevailing in these paleoecosystems which have no equivalent in the modern world. Bone and dentine remains representing five mammalian assemblages dated around 35 ka BP, one of which included a Neandertal specimen, are investigated for Sr/Ca and Ba/Ca of bioapatites. Examination of the N content and U+REE luminescence of bulk material, Ca/P ratios, and Mn and Ca contents of purified samples demonstrates that the Sr/Ca and the Ba/Ca ratios of bone and dentine samples are not significantly altered by diagenesis. As a consequence of the biological discrimination of Sr and Ba in relation to Ca, Sr/Ca and Ba/Ca values are impoverished with increasing trophic position and are strongly correlated within a trophic web. The slopes of the linear regressions between Sr/Ca and Ba/Ca are consistent with modern variability. Furthermore, a statistical difference was found between Ba/Ca of foregut and hindgut herbivores. When coexisting collagen is preserved, the Sr+Ba/Ca and δ15N are strongly correlated. The distribution of values suggests that the δ15N range is mainly controlled by the variability of soil conditions whereas the δ13C range may be related to resource availability.