Spectroscopy of Palaeolithic rock paintings from the Tito Bustillo and El Buxu Caves, Asturias, Spain†

Significant paintings from the Tito Bustillo (Ribadesella, Asturias) and El Buxu (Cardes, Asturias) caves, renowned archaeological sites of the Cantabrian Palaeolithic cave art, were studied by micro-Raman spectroscopy. Auxiliary techniques like infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electronic microscopy combined with energy dispersive X-ray spectrometry were also applied. Haematite (α-Fe2O3) of three granular sizes (<1, <10 and <30 µm) is the main red component of these paintings. Wustite, amorphous carbon, and Mn are additional components of some pigments. Hydroxyapatite was also detected in one pictograph. Calcite, α-quartz and clay minerals are used as filler materials. Particles of anatase are present in some cases. No organic binders were detected. Considering the main components, granular size, and secondary phases with Ni and Mn in the pigments it is concluded that the ochre quarry in the Tito Bustillo cave was not used to make the pigments of the selected paintings. Two figures of this cave seem to have been painted with a similar pigment. A possible relationship between paintings of both caves is discussed. Copyright © 2011 John Wiley & Sons, Ltd.