Diagenetic alterations of Meriones incisors (Rodentia) of El Harhoura 2 cave, Morocco (late Pleistocene–middle Holocene)

Résumé En

Fossil teeth are used for palaeoenvironmental reconstructions. Among the criteria used, the geochemical composition is favoured, because it is said that the enamelis exempt from diagenetic changes. The combined microstructural and chemical analyses of rodent incisors from the cave of El Hahroura 2 (Morocco, Middle Palaeolithic– Neolithic) using scanning electron microscopy, an electron microprobe and FTIR spectroscopy show that all teeth were preserved in apatite. Nevertheless, the microstructure of both dentine and enamel is altered, as well as their chemical composition. Teeth excavated from the upper layers are already diagenetically modified despite being from the Neolithic. Teeth from three older stratigraphic layers are also altered but with a different pattern. Up to now, a direct correlation of the morphological and structural/compositional preservation has not been possible, showing that to use only one criterion to infer the quality of the preservation is not sufficient. Moreover, palaeoecological or palaeoenvironmental reconstructions based on geochemical data without control of the dental microstructure may be biased.