Application of 3-dimensional microscopy and micro-CT scanning to the analysis of Magdalenian portable art on bone and antler

The appearance of portable artistic objects during the Upper Palaeolithic is characterised by a combination of a wide choice of techniques, use of different materials and a diversity of iconographic expression, with many objects made of bone and antler decorated with animal representations. Taphonomic and experimental approaches have been systematically applied in an effort to understand the technical and artistic procedures followed. In this study, we applied a new combination of 3-dimensional microscopy (focus variation optical microscope) and micro-CT scanning to the analysis of two Magdalenian engraved specimens: a reindeer antler from the site of Neschers (France), engraved with the partial image of a horse in left profile, and a horde metatarsal from Courbet Cave, Penne (France), engraved with a horse head also in left profile. Results of the analysis suggest that both the Neschers and Courbet Cave engravings had been prepared before being carved. The overall contours of the horse body/head were incised first, while anatomical features were added afterwards. In the Neschers case, the incision resulted from the repeated scratching of a previously made incision in order to enlarge the engraving, possibly reflecting the engraver's aesthetic sense. The combination of the techniques used in this study is applicable to fragile or unique archaeological specimens. Micro-CT scanning, in particular, provides non-invasive means for identifying engravings that are obscured by encrusted sediment. The application of these techniques can potentially open new avenues for the authentication, technical and gestural recognition and interpretation of incised forms and artistic creativity. (C) 2013 Elsevier Ltd. All rights reserved.